Partial Discharge Acceptance Criteria for New Cable Installations | Feichun Cable<\/title>\n<meta name=\"description\" content=\"Engineering guide to partial discharge acceptance criteria for new shielded cable installations: pass\/fail logic, PDIV, PDEV, apparent charge, sensitivity, localization, noise rejection, commissioning methods and specification clauses.\">\n<meta name=\"keywords\" content=\"partial discharge acceptance criteria, cable PD test pass fail, new cable installation, PDIV, PDEV, apparent charge pC, commissioning test, offline partial discharge, online partial discharge, cable joint testing, termination testing, IEEE 400.3, IEC 60270, Feichun Cable\">\n<meta name=\"robots\" content=\"index,follow,max-image-preview:large\"><link rel=\"canonical\" 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Criteria or Pass\/Fail Thresholds Are Commonly Used for Partial Discharge Measurements on New Cable Installations?\",\"inLanguage\":\"en\",\"datePublished\":\"2026-08-10\",\"dateModified\":\"2026-08-10\",\"author\":{\"@type\":\"Organization\",\"name\":\"Feichun Cable\"},\"publisher\":{\"@type\":\"Organization\",\"name\":\"Feichun Cable\"},\"about\":[\"Partial discharge\",\"Cable commissioning\",\"PDIV\",\"PDEV\",\"IEEE 400.3-2022\",\"IEC 60270:2025\"]}<\/script><\/head><body>\n<header class=\"hero\"><div class=\"wrap\"><div class=\"eyebrow\">Feichun Cable \u00b7 cable-system commissioning engineering<\/div><h1>What Acceptance Criteria or Pass\/Fail Thresholds Are Commonly Used for Partial Discharge Measurements on New Cable Installations?<\/h1><p class=\"lead\">There is no technically defensible universal picocoulomb limit for every newly installed cable circuit. A sound acceptance specification combines a successful withstand test, a stated test waveform and voltage, demonstrated end-to-end detection sensitivity, rejection of external interference, source localization, PD inception and extinction behavior, phase-resolved pattern analysis, and an explicit decision rule for the cable, joints and terminations.<\/p><div class=\"badges\"><span>IEEE 400.3-2022<\/span><span>IEC 60270:2025<\/span><span>PDIV \/ PDEV<\/span><span>Apparent charge<\/span><span>Localization<\/span><span>PRPD<\/span><span>Pass \/ Hold \/ Fail<\/span><span>Commissioning baseline<\/span><\/div><div class=\"meta\"><span>Professional engineering article<\/span><span>Standards status reviewed: 2026-08<\/span><span>No invented product data<\/span><span>4 technical SVG diagrams<\/span><\/div><\/div><\/header>\n<main class=\"wrap\"><nav class=\"toc\"><strong>Engineer\u2019s quick navigation<\/strong><ol><li><a href=\"#answer\">Direct answer<\/a><\/li><li><a href=\"#why\">Why no universal pC limit exists<\/a><\/li><li><a href=\"#standards\">Standards map<\/a><\/li><li><a href=\"#factory-field\">Factory versus field limits<\/a><\/li><li><a href=\"#matrix\">Common decision matrix<\/a><\/li><li><a href=\"#pdiv-pdev\">PDIV and PDEV<\/a><\/li><li><a href=\"#sensitivity\">Sensitivity and calibration<\/a><\/li><li><a href=\"#noise\">Noise and source classification<\/a><\/li><li><a href=\"#methods\">Test-method dependence<\/a><\/li><li><a href=\"#components\">Cable, joint and termination<\/a><\/li><li><a href=\"#long-cable\">Long-circuit localization<\/a><\/li><li><a href=\"#procedure\">Commissioning procedure<\/a><\/li><li><a href=\"#workflow\">Pass\/Hold\/Fail workflow<\/a><\/li><li><a href=\"#report\">Acceptance report<\/a><\/li><li><a href=\"#specification\">Model specification clauses<\/a><\/li><li><a href=\"#applications\">Critical applications<\/a><\/li><li><a href=\"#faq\">FAQ and RFQ data<\/a><\/li><li><a href=\"#sources\">Technical sources<\/a><\/li><\/ol><\/nav>\n\n<section id=\"answer\"><h2>Direct answer: use a multi-parameter acceptance envelope, not a universal pC number<\/h2><blockquote>For a new installed cable system, the most common defensible criterion is: no repeatable, defect-related, localized partial discharge attributable to the cable, a joint or a termination at the specified commissioning voltage, above a detection sensitivity that has been demonstrated for the relevant location. PD that persists at or below normal phase-to-ground operating voltage U<sub>0<\/sub> is normally a reject or rework condition.<\/blockquote>\n<div class=\"cards\"><div class=\"card green\"><div class=\"value\">PASS<\/div><p>Withstand completed; sensitivity demonstrated; no repeatable localized defect PD at the required voltage; no PD remains at U<sub>0<\/sub> on the descending voltage step.<\/p><\/div><div class=\"card gold\"><div class=\"value\">HOLD<\/div><p>Source is weak, intermittent, only above U<sub>0<\/sub>, not localized, or masked by noise. Perform source separation, repeat testing or an agreed complementary diagnostic.<\/p><\/div><div class=\"card red\"><div class=\"value\">FAIL<\/div><p>Repeatable internal or accessory PD is localized at or below U<sub>0<\/sub>, PDEV is at or below U<sub>0<\/sub>, activity grows materially with voltage, or the withstand test fails.<\/p><\/div><div class=\"card\"><div class=\"value\">INVALID<\/div><p>The required sensitivity cannot be demonstrated, background exceeds the criterion, calibration is incomplete, or the test waveform differs from the approved procedure.<\/p><\/div><\/div>\n<p class=\"warn\"><strong>Do not write \u201cPD shall be below 10 pC\u201d by itself.<\/strong> Without voltage, waveform, bandwidth, calibration method, background level, cable length, sensor location, source-location rule and treatment of external corona, that sentence is not an auditable acceptance criterion.<\/p><\/section>\n\n<section id=\"why\"><h2>Why field measurements do not have one universal picocoulomb threshold<\/h2><div class=\"scroll\"><table><caption>Variables that change the measured magnitude and its meaning<\/caption><thead><tr><th>Variable<\/th><th>Effect on recorded PD<\/th><th>Acceptance implication<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">Circuit length<\/td><td>High-frequency pulses attenuate and disperse as they propagate; distant defects may appear smaller.<\/td><td>A terminal sensitivity check does not automatically prove sensitivity at every joint.<\/td><\/tr><tr><td class=\"key\">Accessory interfaces<\/td><td>Impedance changes create reflections and multiple arrivals.<\/td><td>Location algorithms and sensor placement must account for the circuit topology.<\/td><\/tr><tr><td class=\"key\">Measurement bandwidth<\/td><td>IEC 60270 charge-based systems, HFCT\/UHF sensors and online monitors observe different spectral content.<\/td><td>Numbers from unlike systems are not directly interchangeable.<\/td><\/tr><tr><td class=\"key\">Voltage waveform<\/td><td>Power-frequency, resonant, VLF and DAC excitation produce different charge dynamics and phase references.<\/td><td>Limits and baselines must be attached to the named method.<\/td><\/tr><tr><td class=\"key\">Background interference<\/td><td>Switching supplies, radio signals, corona, grounding loops and test equipment may imitate PD.<\/td><td>A raw amplitude crossing is not a failure until the source is classified.<\/td><\/tr><tr><td class=\"key\">Defect physics<\/td><td>A small internal void, surface discharge, floating electrode and external corona have different risk.<\/td><td>Pattern, repetition, voltage dependence and location matter as much as q<sub>IEC<\/sub>.<\/td><\/tr><tr><td class=\"key\">Temperature and history<\/td><td>Thermal state, voltage dwell and previous overvoltage affect inception and extinction.<\/td><td>Record the sequence and allow the specified stabilization time.<\/td><\/tr><\/tbody><\/table><\/div>\n<p class=\"note\">Apparent charge in pC is a calibrated terminal quantity representing the equivalent charge transfer that would create the observed terminal response. It is not a direct measurement of the microscopic charge inside the defect.<\/p><\/section>\n\n<section id=\"standards\"><h2>Which standards control the acceptance logic?<\/h2><div class=\"scroll\"><table><caption>Standards and their proper roles<\/caption><thead><tr><th>Document<\/th><th>Current public status<\/th><th>Role<\/th><th>What it does not provide<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">IEEE 400.3-2022<\/td><td class=\"source\">Active; published 2023<\/td><td>Guide for online or externally energized field PD detection, measurement and location on installed shielded cable systems, including cable, joints and terminations.<\/td><td class=\"tbc\">No single universal field pC pass\/fail value.<\/td><\/tr><tr><td class=\"key\">IEC 60270:2025<\/td><td class=\"source\">Edition 4.0<\/td><td>Charge-based quantities, circuits, frequency ranges, calibration, instruments, procedures and interference discrimination.<\/td><td class=\"tbc\">No product-independent installed-cable acceptance limit.<\/td><\/tr><tr><td class=\"key\">IEC 60502-2<\/td><td class=\"source\">2014+A1:2024 with COR1:2026<\/td><td>Product requirements for extruded-insulation cables from 6 kV up to 30 kV rated voltage classes.<\/td><td class=\"tbc\">Factory values are not automatically field thresholds for a complete installed circuit.<\/td><\/tr><tr><td class=\"key\">IEC 60840<\/td><td class=\"source\">2020+A1:2023; corrected 2025<\/td><td>Cable systems above 30 kV up to 150 kV and their accessories.<\/td><td class=\"tbc\">Does not justify importing a lower-voltage factory threshold without the applicable system procedure.<\/td><\/tr><tr><td class=\"key\">IEC 62067:2022<\/td><td class=\"source\">Edition 3.0<\/td><td>Cable systems above 150 kV up to 500 kV and their accessories.<\/td><td class=\"tbc\">Commissioning remains system- and project-specific.<\/td><\/tr><tr><td class=\"key\">ANSI\/NETA ATS-2025<\/td><td class=\"source\">Current acceptance-testing specification<\/td><td>Framework for suitability for initial energization, with medium-voltage cable acceptance tables and reliability guidance.<\/td><td class=\"tbc\">Its public scope does not establish one universal PD amplitude.<\/td><\/tr><tr><td class=\"key\">IEEE 400.4<\/td><td class=\"source\">DAC field-testing guide under revision<\/td><td>Framework for damped AC field testing and PD diagnostics.<\/td><td class=\"tbc\">Results must remain tied to the DAC waveform and procedure.<\/td><\/tr><\/tbody><\/table><\/div><\/section>\n\n<div class=\"svg\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 1900 920\" role=\"img\" aria-label=\"Factory and field partial discharge acceptance hierarchy\"><defs><marker id=\"a1\" markerWidth=\"12\" markerHeight=\"12\" refX=\"10\" refY=\"4\" orient=\"auto\"><path d=\"M0 0L12 4L0 8Z\" fill=\"#d9edf0\"\/><\/marker><\/defs><rect width=\"1900\" height=\"920\" fill=\"#06131b\"\/><g font-family=\"Arial,Helvetica\"><text x=\"55\" y=\"66\" fill=\"#55dff7\" font-size=\"36\" font-weight=\"700\">PD acceptance hierarchy: product proof is not the same as installed-system acceptance<\/text><rect x=\"95\" y=\"145\" width=\"510\" height=\"250\" rx=\"22\" fill=\"#0d1921\" stroke=\"#f0c865\" stroke-width=\"6\"\/><text x=\"145\" y=\"205\" fill=\"#f0c865\" font-size=\"29\" font-weight=\"700\">Factory product tests<\/text><text x=\"145\" y=\"260\" fill=\"#e8f3f5\" font-size=\"22\">Controlled screened laboratory<\/text><text x=\"145\" y=\"305\" fill=\"#e8f3f5\" font-size=\"22\">Short defined specimen<\/text><text x=\"145\" y=\"350\" fill=\"#e8f3f5\" font-size=\"22\">IEC 60270-comparable circuit<\/text><rect x=\"695\" y=\"145\" width=\"510\" height=\"250\" rx=\"22\" fill=\"#0d1921\" stroke=\"#55dff7\" stroke-width=\"6\"\/><text x=\"745\" y=\"205\" fill=\"#55dff7\" font-size=\"29\" font-weight=\"700\">Installed-system test<\/text><text x=\"745\" y=\"260\" fill=\"#e8f3f5\" font-size=\"22\">Cable + joints + terminations<\/text><text x=\"745\" y=\"305\" fill=\"#e8f3f5\" font-size=\"22\">Attenuation and reflections<\/text><text x=\"745\" y=\"350\" fill=\"#e8f3f5\" font-size=\"22\">Site noise and access limits<\/text><rect x=\"1295\" y=\"145\" width=\"510\" height=\"250\" rx=\"22\" fill=\"#0d1921\" stroke=\"#a6ded9\" stroke-width=\"6\"\/><text x=\"1345\" y=\"205\" fill=\"#a6ded9\" font-size=\"29\" font-weight=\"700\">Acceptance envelope<\/text><text x=\"1345\" y=\"260\" fill=\"#e8f3f5\" font-size=\"22\">Voltage + withstand<\/text><text x=\"1345\" y=\"305\" fill=\"#e8f3f5\" font-size=\"22\">Sensitivity + localization<\/text><text x=\"1345\" y=\"350\" fill=\"#e8f3f5\" font-size=\"22\">PDIV\/PDEV + PRPD + trend<\/text><path d=\"M605 270H685M1205 270H1285\" stroke=\"#d9edf0\" stroke-width=\"7\" marker-end=\"url(#a1)\"\/><rect x=\"230\" y=\"530\" width=\"1440\" height=\"220\" rx=\"24\" fill=\"#071821\" stroke=\"#284b5b\" stroke-width=\"5\"\/><text x=\"300\" y=\"595\" fill=\"#ff9297\" font-size=\"28\" font-weight=\"700\">Critical boundary<\/text><text x=\"300\" y=\"650\" fill=\"#e8f3f5\" font-size=\"23\">A 5 pC or 10 pC factory benchmark can be a useful reference only when the field circuit can demonstrate<\/text><text x=\"300\" y=\"692\" fill=\"#e8f3f5\" font-size=\"23\">equal or better detection at the defect location under a comparable measurement definition and test voltage.<\/text><text x=\"420\" y=\"840\" fill=\"#a6ded9\" font-size=\"24\">The commissioning baseline should be retained for future condition comparison.<\/text><\/g><\/svg><div class=\"svg-caption\">Figure 1 \u2014 How factory evidence, field measurement conditions and the acceptance decision fit together.<\/div><\/div>\n\n<section id=\"factory-field\"><h2>Factory limits versus field acceptance: the numbers engineers often confuse<\/h2><div class=\"scroll\"><table><caption>Reference values and correct use<\/caption><thead><tr><th>Context<\/th><th>Commonly referenced value<\/th><th>Proper engineering use<\/th><th>Misuse to avoid<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">IEC 60502-2 routine cable test<\/td><td class=\"derived\">Less than 10 pC at 1.73 U<sub>0<\/sub><\/td><td>Factory routine benchmark on a defined cable specimen using the prescribed measurement method.<\/td><td class=\"tbc\">Do not automatically apply it at one end of a long installed circuit.<\/td><\/tr><tr><td class=\"key\">IEC 60502-2 type-test sequence<\/td><td class=\"derived\">5 pC reference level at 1.73 U<sub>0<\/sub><\/td><td>Factory type-test reference associated with the specified sequence and specimen.<\/td><td class=\"tbc\">Do not present it as a universal commissioning limit.<\/td><\/tr><tr><td class=\"key\">Accessory design\/production tests<\/td><td>Low-pC limits and specified extinction voltage are common in applicable joint and termination standards.<\/td><td>Use the exact accessory standard, voltage class, edition and approved drawing.<\/td><td class=\"tbc\">Do not quote a generic accessory number without the applicable document.<\/td><\/tr><tr><td class=\"key\">Offline installed-system PD<\/td><td>No universal pC value<\/td><td>Specify absence of localized defect PD above a verified sensitivity at the test voltage, plus PDIV\/PDEV and pattern rules.<\/td><td class=\"tbc\">Do not accept an unlocalized terminal amplitude alone.<\/td><\/tr><tr><td class=\"key\">Online PD survey<\/td><td>No universal pC-equivalent value<\/td><td>Use multi-sensor correlation, pattern, location, operating condition and baseline\/trend.<\/td><td class=\"tbc\">Do not compare an HFCT reading directly with an IEC 60270 factory pC number.<\/td><\/tr><\/tbody><\/table><\/div>\n<p class=\"warn\"><strong>Contract rule:<\/strong> if a project adopts a 10 pC field criterion, the test provider must demonstrate end-to-end detection at or below 10 pC at each relevant evaluation location. If that sensitivity cannot be proven, the numerical criterion is not technically enforceable and the result is invalid\u2014not a pass.<\/p><\/section>\n\n<section id=\"matrix\"><h2>Common acceptance matrix for a new installed cable circuit<\/h2><div class=\"scroll\"><table><caption>Recommended Pass \/ Hold \/ Fail \/ Invalid classification<\/caption><thead><tr><th>Observation<\/th><th>Typical classification<\/th><th>Engineering rationale<\/th><th>Required action<\/th><\/tr><\/thead><tbody><tr><td>Withstand completed; required sensitivity demonstrated; no localized defect activity at the specified voltage<\/td><td class=\"pass\">PASS<\/td><td>Electrical strength and PD diagnostic conditions both meet the approved procedure.<\/td><td>Save raw data and establish the commissioning baseline.<\/td><\/tr><tr><td>No PD on the descending step at U<sub>0<\/sub>; any prior activity is confirmed as external corona<\/td><td class=\"pass\">PASS<\/td><td>Source attribution prevents external interference being mistaken for insulation PD.<\/td><td>Document evidence used for classification.<\/td><\/tr><tr><td>Repeatable cable\/accessory PD begins or persists at or below U<sub>0<\/sub><\/td><td class=\"fail\">FAIL \/ REWORK<\/td><td>The defect is active under normal electrical stress.<\/td><td>Localize, inspect, repair or replace, then repeat the full agreed test.<\/td><\/tr><tr><td>PDEV is at or below U<sub>0<\/sub><\/td><td class=\"fail\">FAIL \/ REWORK<\/td><td>Once initiated, discharge remains active at normal operating voltage.<\/td><td>Do not energize until disposition is approved.<\/td><\/tr><tr><td>Localized activity only above U<sub>0<\/sub>, weak but repeatable<\/td><td class=\"hold\">HOLD \/ ENGINEERING REVIEW<\/td><td>It may reveal a defect with operating margin, but risk depends on voltage, type and growth behavior.<\/td><td>Apply the project\u2019s required PDEV margin and defect-specific rules.<\/td><\/tr><tr><td>Unlocalized activity or conflicting sensor locations<\/td><td class=\"hold\">HOLD<\/td><td>Defect attribution is incomplete.<\/td><td>Reconfigure sensors, perform time-of-flight analysis or use complementary detection.<\/td><\/tr><tr><td>Background noise is above the contractual threshold<\/td><td class=\"fail\">INVALID TEST<\/td><td>Absence of recorded PD cannot prove absence of detectable PD.<\/td><td>Reduce noise, change timing\/location\/bandwidth, or reschedule.<\/td><\/tr><tr><td>Calibration pulse is visible at the near end but not verified across the circuit<\/td><td class=\"fail\">INVALID FOR REMOTE POINTS<\/td><td>Long-cable attenuation can hide a distant defect.<\/td><td>Verify at relevant joints\/ends or model and validate the transfer function.<\/td><\/tr><tr><td>Breakdown, flashover or protective trip during withstand<\/td><td class=\"fail\">FAIL<\/td><td>The circuit did not withstand the approved test stress.<\/td><td>Investigate and repair before any repeat test.<\/td><\/tr><\/tbody><\/table><\/div><\/section>\n\n<section id=\"pdiv-pdev\"><h2>PDIV and PDEV often carry more risk information than q<sub>max<\/sub><\/h2><p>Partial-discharge inception voltage (PDIV) is the increasing-voltage level at which specified, repeatable PD first appears. Partial-discharge extinction voltage (PDEV) is the decreasing-voltage level below which that activity ceases. Because many defects exhibit hysteresis, PDEV is normally the more direct question for operating risk.<\/p><div class=\"scroll\"><table><caption>Interpreting inception and extinction<\/caption><thead><tr><th>Finding<\/th><th>Interpretation<\/th><th>Typical disposition<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">No PD through the specified test voltage<\/td><td>Best outcome, provided sensitivity and noise requirements were satisfied.<\/td><td class=\"pass\">Pass.<\/td><\/tr><tr><td class=\"key\">PDIV > U<sub>0<\/sub>, PDEV > U<sub>0<\/sub><\/td><td>Activity exists only above normal stress; the margin may or may not meet the project requirement.<\/td><td class=\"hold\">Review against specified margin and defect type.<\/td><\/tr><tr><td class=\"key\">PDIV > U<sub>0<\/sub>, PDEV \u2264 U<sub>0<\/sub><\/td><td>Overvoltage can trigger activity that remains active at normal stress.<\/td><td class=\"fail\">Reject or rework.<\/td><\/tr><tr><td class=\"key\">PDIV \u2264 U<sub>0<\/sub><\/td><td>Defect is capable of initiating during normal operation.<\/td><td class=\"fail\">Reject or rework.<\/td><\/tr><tr><td class=\"key\">PDIV\/PDEV cannot be determined because of noise<\/td><td>The voltage threshold is not measurable.<\/td><td class=\"fail\">Invalid; improve the test condition.<\/td><\/tr><\/tbody><\/table><\/div>\n<p class=\"note\">Some project programs require PDEV above a contractual margin such as 1.3 U<sub>0<\/sub> or 1.5 U<sub>0<\/sub>. Such a margin can be conservative and useful, but it must be identified as a project or component-specific requirement\u2014not attributed as a universal IEEE 400.3 threshold.<\/p><\/section>\n\n<div class=\"svg\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 1900 980\" role=\"img\" aria-label=\"PDIV PDEV voltage ladder and phase resolved partial discharge pattern\"><rect width=\"1900\" height=\"980\" fill=\"#06131b\"\/><g font-family=\"Arial,Helvetica\"><text x=\"55\" y=\"64\" fill=\"#55dff7\" font-size=\"36\" font-weight=\"700\">Voltage ladder, PDIV\/PDEV hysteresis and phase-resolved evidence<\/text><line x1=\"130\" y1=\"720\" x2=\"1020\" y2=\"720\" stroke=\"#d9edf0\" stroke-width=\"5\"\/><line x1=\"130\" y1=\"720\" x2=\"130\" y2=\"150\" stroke=\"#d9edf0\" stroke-width=\"5\"\/><path d=\"M170 680H300V600H430V500H560V360H690V260H820V360H690V500H560V600H430V680H300\" fill=\"none\" stroke=\"#55dff7\" stroke-width=\"12\"\/><line x1=\"130\" y1=\"500\" x2=\"1020\" y2=\"500\" stroke=\"#f0c865\" stroke-width=\"4\" stroke-dasharray=\"18 12\"\/><text x=\"150\" y=\"485\" fill=\"#f0c865\" font-size=\"24\" font-weight=\"700\">U\u2080<\/text><circle cx=\"560\" cy=\"360\" r=\"18\" fill=\"#ff9297\"\/><text x=\"585\" y=\"345\" fill=\"#ff9297\" font-size=\"22\" font-weight=\"700\">PDIV on rising voltage<\/text><circle cx=\"430\" cy=\"600\" r=\"18\" fill=\"#a6ded9\"\/><text x=\"455\" y=\"640\" fill=\"#a6ded9\" font-size=\"22\" font-weight=\"700\">PDEV on descending voltage<\/text><text x=\"170\" y=\"805\" fill=\"#e8f3f5\" font-size=\"21\">Voltage steps require dwell time, synchronized acquisition and background recording.<\/text><rect x=\"1120\" y=\"150\" width=\"650\" height=\"570\" rx=\"18\" fill=\"#0d1921\" stroke=\"#284b5b\" stroke-width=\"5\"\/><line x1=\"1190\" y1=\"650\" x2=\"1705\" y2=\"650\" stroke=\"#d9edf0\" stroke-width=\"4\"\/><line x1=\"1190\" y1=\"650\" x2=\"1190\" y2=\"220\" stroke=\"#d9edf0\" stroke-width=\"4\"\/><path d=\"M1190 435Q1320 240 1450 435T1710 435\" fill=\"none\" stroke=\"#55dff7\" stroke-width=\"5\"\/><g fill=\"#ff9297\"><circle cx=\"1260\" cy=\"350\" r=\"10\"\/><circle cx=\"1290\" cy=\"318\" r=\"9\"\/><circle cx=\"1325\" cy=\"300\" r=\"12\"\/><circle cx=\"1485\" cy=\"515\" r=\"10\"\/><circle cx=\"1525\" cy=\"548\" r=\"12\"\/><circle cx=\"1570\" cy=\"530\" r=\"9\"\/><\/g><text x=\"1220\" y=\"205\" fill=\"#55dff7\" font-size=\"25\" font-weight=\"700\">Illustrative PRPD map<\/text><text x=\"1210\" y=\"690\" fill=\"#e8f3f5\" font-size=\"20\">0\u00b0<\/text><text x=\"1425\" y=\"690\" fill=\"#e8f3f5\" font-size=\"20\">180\u00b0<\/text><text x=\"1660\" y=\"690\" fill=\"#e8f3f5\" font-size=\"20\">360\u00b0<\/text><rect x=\"185\" y=\"855\" width=\"1530\" height=\"75\" rx=\"14\" fill=\"#071821\" stroke=\"#ff9297\" stroke-width=\"4\"\/><text x=\"245\" y=\"902\" fill=\"#ff9297\" font-size=\"22\">A PRPD pattern supports classification; it does not replace source localization or a proven sensitivity level.<\/text><\/g><\/svg><div class=\"svg-caption\">Figure 2 \u2014 A controlled up\/down voltage sequence reveals inception, extinction and phase-resolved behavior.<\/div><\/div>\n\n<section id=\"sensitivity\"><h2>Detection sensitivity is part of the acceptance criterion<\/h2><div class=\"scroll\"><table><caption>What a defensible sensitivity demonstration should contain<\/caption><thead><tr><th>Requirement<\/th><th>Engineering purpose<\/th><th>Evidence in report<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">Known calibrator or reference pulse<\/td><td>Checks measurement-chain response and scaling.<\/td><td>Calibrator identity, charge setting, validity and connection point.<\/td><\/tr><tr><td class=\"key\">Relevant injection location<\/td><td>Tests the propagation path from a potential defect to the sensor.<\/td><td>Near end, far end and accessible joint locations as required.<\/td><\/tr><tr><td class=\"key\">End-to-end visibility<\/td><td>Proves the contractual threshold is detectable after attenuation.<\/td><td>Signal-to-noise ratio and recovered magnitude at each channel.<\/td><\/tr><tr><td class=\"key\">Frequency response<\/td><td>Documents how the selected bandwidth changes pulse amplitude and shape.<\/td><td>Filter settings, bandwidth, coupling device and sensor transfer data.<\/td><\/tr><tr><td class=\"key\">Background before and during energization<\/td><td>Separates ambient noise, source noise and voltage-dependent events.<\/td><td>Noise floor at each voltage step and with source energized\/de-energized.<\/td><\/tr><tr><td class=\"key\">Timing synchronization<\/td><td>Enables time-of-flight location and phase-resolved mapping.<\/td><td>Clock reference, phase reference and channel timing verification.<\/td><\/tr><tr><td class=\"key\">Repeatability check<\/td><td>Detects unstable wiring, grounding or processing artifacts.<\/td><td>Repeated calibration response before and after the test.<\/td><\/tr><\/tbody><\/table><\/div>\n<p class=\"warn\"><strong>Calibration boundary:<\/strong> injecting a charge at one terminal calibrates the response at that injection point. It does not recreate every defect pulse spectrum and does not prove the same apparent-charge sensitivity at a remote joint unless the propagation path is verified.<\/p><\/section>\n\n<section id=\"noise\"><h2>External corona and electromagnetic noise must not become false failures<\/h2><div class=\"scroll\"><table><caption>Source-separation indicators<\/caption><thead><tr><th>Possible source<\/th><th>Useful evidence<\/th><th>Typical response<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">Internal insulation void<\/td><td>Stable bipolar phase windows, voltage dependence, repeated location inside cable\/accessory.<\/td><td>Defect-related; disposition by PDIV\/PDEV, level and location.<\/td><\/tr><tr><td class=\"key\">Surface discharge at termination<\/td><td>Pattern changes with humidity\/cleaning; optical or acoustic correlation near stress-control surface.<\/td><td>Inspect assembly, contamination, clearance and stress cone.<\/td><\/tr><tr><td class=\"key\">External corona<\/td><td>Localized in air near exposed energized hardware; often unipolar pattern and sensitive to geometry.<\/td><td>Correct test setup or document exclusion from cable-system PD.<\/td><\/tr><tr><td class=\"key\">Floating metal<\/td><td>Distinct repetitive pattern; may change when bonding or mechanical contact changes.<\/td><td>Inspect shields, grounds, screens and test connections.<\/td><\/tr><tr><td class=\"key\">Switching or radio interference<\/td><td>Appears on reference antenna or multiple unrelated channels; not tied consistently to test voltage.<\/td><td>Use time gating, correlation and narrower justified bandwidth.<\/td><\/tr><tr><td class=\"key\">Test-source discharge<\/td><td>Appears with source energized before the cable is connected or follows source-side sensor.<\/td><td>Repair, shield or reconfigure source before acceptance testing.<\/td><\/tr><\/tbody><\/table><\/div><\/section>\n\n<section id=\"methods\"><h2>Offline power-frequency, VLF, DAC and online PD are not numerically interchangeable<\/h2><div class=\"scroll\"><table><caption>Method comparison for new-circuit commissioning<\/caption><thead><tr><th>Method<\/th><th>Strength<\/th><th>Limitation<\/th><th>Acceptance rule<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">Power-frequency \/ resonant AC<\/td><td>Electrical stress and phase behavior are comparatively close to service-frequency conditions.<\/td><td>Equipment size and circuit capacitance can be demanding.<\/td><td>Tie pC, PDIV\/PDEV and withstand voltage to the approved resonant setup.<\/td><\/tr><tr><td class=\"key\">VLF sinusoidal<\/td><td>Compact source for long capacitive circuits.<\/td><td>Frequency-dependent charge transport and accessories may respond differently.<\/td><td>Use method-specific voltage, duration and interpretation; do not transplant a factory power-frequency limit.<\/td><\/tr><tr><td class=\"key\">DAC<\/td><td>Useful for PD inception, extinction and location with a decaying oscillatory waveform.<\/td><td>Voltage varies during the oscillation; charge estimation and pattern construction are system-specific.<\/td><td>Follow the stated DAC guide\/procedure and retain waveform parameters.<\/td><\/tr><tr><td class=\"key\">Online at operating voltage<\/td><td>No outage or external overvoltage; observes real loading and environment.<\/td><td>Highest interference burden and often non-conventional sensors.<\/td><td>Use location, correlation, classification and trend; avoid universal pC-equivalent pass\/fail.<\/td><\/tr><tr><td class=\"key\">Monitored withstand<\/td><td>Combines voltage withstand with real-time PD warning and localization.<\/td><td>Requires a predetermined stop rule and trained interpretation.<\/td><td>Define maximum voltage, dwell, alarm\/stop criteria and post-test PDEV check.<\/td><\/tr><\/tbody><\/table><\/div><\/section>\n\n<section id=\"components\"><h2>Acceptance must identify whether the source is cable, joint or termination<\/h2><div class=\"scroll\"><table><caption>Component-specific failure mechanisms<\/caption><thead><tr><th>Component<\/th><th>Typical new-installation defect<\/th><th>PD evidence<\/th><th>Corrective focus<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">Extruded cable<\/td><td>Contamination, protrusion, insulation void, semiconductive-screen defect or installation damage.<\/td><td>Repeatable location in a cable section; characteristic phase and voltage dependence.<\/td><td>Confirm route damage and manufacturing traceability; replace affected length where required.<\/td><\/tr><tr><td class=\"key\">Premoulded joint<\/td><td>Incorrect positioning, trapped air, contamination, screen cut error or inadequate interface pressure.<\/td><td>Pulse location at joint; possible surface\/interface pattern.<\/td><td>Open under controlled procedure, inspect workmanship and install a new approved kit.<\/td><\/tr><tr><td class=\"key\">Heat-shrink or cold-shrink joint<\/td><td>Moisture, wrinkles, incorrect overlap, voids or poor stress-control geometry.<\/td><td>Joint-localized activity with voltage-dependent repetition.<\/td><td>Verify preparation dimensions, environmental controls and installer record.<\/td><\/tr><tr><td class=\"key\">Termination<\/td><td>Stress-cone misplacement, contamination, moisture, inadequate clearance or grounding error.<\/td><td>Electrical PD plus possible acoustic\/optical indication near exposed end.<\/td><td>Distinguish internal\/interface discharge from external air corona.<\/td><\/tr><tr><td class=\"key\">Bonding link \/ sheath connection<\/td><td>Floating screen, loose ground, incorrect cross-bonding or test-lead geometry.<\/td><td>Floating-metal patterns or false location caused by reflections.<\/td><td>Correct the bonding system and repeat calibration before retest.<\/td><\/tr><\/tbody><\/table><\/div><\/section>\n\n<div class=\"svg\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 1900 920\" role=\"img\" aria-label=\"Partial discharge localization on a cable with terminations and joints\"><defs><marker id=\"a3\" markerWidth=\"12\" markerHeight=\"12\" refX=\"10\" refY=\"4\" orient=\"auto\"><path d=\"M0 0L12 4L0 8Z\" fill=\"#ff9297\"\/><\/marker><\/defs><rect width=\"1900\" height=\"920\" fill=\"#06131b\"\/><g font-family=\"Arial,Helvetica\"><text x=\"55\" y=\"64\" fill=\"#55dff7\" font-size=\"36\" font-weight=\"700\">PD localization across terminations, cable sections and joints<\/text><path d=\"M180 470H1720\" stroke=\"#27383f\" stroke-width=\"86\"\/><path d=\"M180 470H1720\" stroke=\"#55dff7\" stroke-width=\"24\"\/><path d=\"M180 380V560M1720 380V560\" stroke=\"#f0c865\" stroke-width=\"26\"\/><g fill=\"#a6ded9\" stroke=\"#071821\" stroke-width=\"8\"><rect x=\"590\" y=\"390\" width=\"150\" height=\"160\" rx=\"28\"\/><rect x=\"1160\" y=\"390\" width=\"150\" height=\"160\" rx=\"28\"\/><\/g><g fill=\"#e8f3f5\" font-size=\"21\"><text x=\"105\" y=\"625\">Termination A<\/text><text x=\"600\" y=\"625\">Joint J1<\/text><text x=\"1170\" y=\"625\">Joint J2<\/text><text x=\"1640\" y=\"625\">Termination B<\/text><\/g><circle cx=\"1215\" cy=\"440\" r=\"18\" fill=\"#ff9297\"\/><path d=\"M1215 420Q1080 250 820 330T260 270\" fill=\"none\" stroke=\"#ff9297\" stroke-width=\"7\" marker-end=\"url(#a3)\"\/><path d=\"M1215 420Q1370 270 1660 330\" fill=\"none\" stroke=\"#f0c865\" stroke-width=\"7\" marker-end=\"url(#a3)\"\/><rect x=\"130\" y=\"160\" width=\"330\" height=\"120\" rx=\"18\" fill=\"#0d1921\" stroke=\"#55dff7\" stroke-width=\"5\"\/><text x=\"180\" y=\"210\" fill=\"#55dff7\" font-size=\"23\" font-weight=\"700\">HFCT \/ coupling sensor<\/text><text x=\"180\" y=\"252\" fill=\"#e8f3f5\" font-size=\"20\">Time stamp t\u2081<\/text><rect x=\"1460\" y=\"160\" width=\"330\" height=\"120\" rx=\"18\" fill=\"#0d1921\" stroke=\"#f0c865\" stroke-width=\"5\"\/><text x=\"1510\" y=\"210\" fill=\"#f0c865\" font-size=\"23\" font-weight=\"700\">Remote sensor<\/text><text x=\"1510\" y=\"252\" fill=\"#e8f3f5\" font-size=\"20\">Time stamp t\u2082<\/text><rect x=\"360\" y=\"730\" width=\"1180\" height=\"110\" rx=\"18\" fill=\"#071821\" stroke=\"#284b5b\" stroke-width=\"5\"\/><text x=\"425\" y=\"780\" fill=\"#a6ded9\" font-size=\"23\">Location uses propagation velocity and arrival-time difference, then checks reflections against the known topology.<\/text><text x=\"425\" y=\"818\" fill=\"#ff9297\" font-size=\"21\">A magnitude without a defensible location should normally be held for further investigation.<\/text><\/g><\/svg><div class=\"svg-caption\">Figure 3 \u2014 Multi-ended or distributed sensing improves source attribution and exposes attenuation at remote accessories.<\/div><\/div>\n\n<section id=\"long-cable\"><h2>Long circuits: why the farthest joint may govern test validity<\/h2><div class=\"scroll\"><table><caption>Long-cable acceptance controls<\/caption><thead><tr><th>Risk<\/th><th>Consequence<\/th><th>Mitigation<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">Pulse attenuation<\/td><td>A remote defect falls below the noise floor.<\/td><td>Use sensors at both ends or accessible joints; verify transfer sensitivity.<\/td><\/tr><tr><td class=\"key\">Dispersion<\/td><td>Pulse broadens and peak amplitude falls.<\/td><td>Use validated bandwidth and location-dependent correction cautiously.<\/td><\/tr><tr><td class=\"key\">Multiple reflections<\/td><td>A single defect appears at several times or locations.<\/td><td>Build a topology\/reflection map before classifying sources.<\/td><\/tr><tr><td class=\"key\">Cross-bonding sections<\/td><td>Bonding hardware changes propagation and sensor response.<\/td><td>Record link-box configuration and use section-specific calibration.<\/td><\/tr><tr><td class=\"key\">Parallel circuits<\/td><td>Coupled pulses may be assigned to the wrong feeder.<\/td><td>Correlate simultaneously across circuits and use reference sensors.<\/td><\/tr><tr><td class=\"key\">Unavailable joints<\/td><td>Direct injection or local sensor placement is impossible.<\/td><td>Document the residual blind zone and obtain owner approval of the limitation.<\/td><\/tr><\/tbody><\/table><\/div>\n<div class=\"formula\">Illustrative two-ended location relation\nx \u2248 (L + v\u00b7\u0394t) \/ 2\nwhere x = distance from the first synchronized sensor, L = cable-section length,\nv = verified propagation velocity, and \u0394t = difference in first-arrival times.\n\nThis relation is only as reliable as the topology, synchronization, velocity estimate and first-arrival identification.<\/div><\/section>\n\n<section id=\"procedure\"><h2>Recommended commissioning test sequence<\/h2><div class=\"scroll\"><table><caption>Minimum procedure for an auditable PD acceptance test<\/caption><thead><tr><th>Step<\/th><th>Action<\/th><th>Acceptance checkpoint<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">1. Document review<\/td><td>Confirm cable and accessory standards, rated voltage, U<sub>0<\/sub>, lengths, joint map, bonding, prior factory reports and approved test method.<\/td><td>All identifiers match the installed circuit.<\/td><\/tr><tr><td class=\"key\">2. Physical inspection<\/td><td>Inspect terminations, grounds, link boxes, phase clearances and test connections.<\/td><td>No visible condition that would invalidate or endanger the test.<\/td><\/tr><tr><td class=\"key\">3. Background survey<\/td><td>Record sensors with source off, auxiliary systems in relevant states and reference antenna active.<\/td><td>Noise is below or separable from the contractual sensitivity.<\/td><\/tr><tr><td class=\"key\">4. Calibration\/sensitivity<\/td><td>Inject the reference signal at agreed locations and verify every acquisition channel.<\/td><td>End-to-end detection requirement is met.<\/td><\/tr><tr><td class=\"key\">5. Voltage ramp<\/td><td>Raise voltage in controlled steps with defined dwell, recording q, pulse rate, phase pattern and location.<\/td><td>No stop criterion is crossed.<\/td><\/tr><tr><td class=\"key\">6. Withstand dwell<\/td><td>Hold the specified voltage and duration while monitoring PD and leakage\/protection signals.<\/td><td>Withstand passes and no prohibited localized PD develops.<\/td><\/tr><tr><td class=\"key\">7. Descending steps<\/td><td>Reduce voltage and identify PDEV, including a dwell at U<sub>0<\/sub>.<\/td><td>No defect PD persists at U<sub>0<\/sub>; required PDEV margin is met.<\/td><\/tr><tr><td class=\"key\">8. Post-check<\/td><td>Repeat calibration, confirm instrument state and inspect terminations.<\/td><td>Measurement chain remained valid throughout.<\/td><\/tr><tr><td class=\"key\">9. Disposition<\/td><td>Classify each source as cable, accessory, external, interference or unresolved.<\/td><td>Pass\/Hold\/Fail is supported by traceable evidence.<\/td><\/tr><\/tbody><\/table><\/div><\/section>\n\n<section id=\"workflow\"><h2>A practical decision workflow<\/h2><div class=\"scroll\"><table><caption>Decision gates<\/caption><thead><tr><th>Gate<\/th><th>Question<\/th><th>Yes<\/th><th>No<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">Validity<\/td><td>Was the specified waveform used and was sensitivity demonstrated?<\/td><td>Continue.<\/td><td class=\"fail\">Invalid; correct the setup.<\/td><\/tr><tr><td class=\"key\">Withstand<\/td><td>Did the circuit complete the required voltage and duration?<\/td><td>Continue.<\/td><td class=\"fail\">Fail and investigate.<\/td><\/tr><tr><td class=\"key\">Source<\/td><td>Is recorded activity repeatable and attributable to the cable system?<\/td><td>Localize and classify.<\/td><td>Document external\/noise evidence or hold if unresolved.<\/td><\/tr><tr><td class=\"key\">Operating stress<\/td><td>Does defect PD occur or persist at\/below U<sub>0<\/sub>?<\/td><td class=\"fail\">Fail\/rework.<\/td><td>Assess margin above U<sub>0<\/sub>.<\/td><\/tr><tr><td class=\"key\">Margin<\/td><td>Does PDEV exceed the project-required margin?<\/td><td>Assess amplitude, pattern and stability.<\/td><td class=\"hold\">Hold or fail per specification.<\/td><\/tr><tr><td class=\"key\">Final evidence<\/td><td>Are location, PRPD, voltage history and raw files complete?<\/td><td class=\"pass\">Approve pass if all gates meet criteria.<\/td><td class=\"hold\">Hold pending a complete record.<\/td><\/tr><\/tbody><\/table><\/div><\/section>\n\n<div class=\"svg\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 1900 980\" role=\"img\" aria-label=\"Pass hold fail decision workflow for cable partial discharge acceptance\"><defs><marker id=\"a4\" markerWidth=\"12\" markerHeight=\"12\" refX=\"10\" refY=\"4\" orient=\"auto\"><path d=\"M0 0L12 4L0 8Z\" fill=\"#d9edf0\"\/><\/marker><\/defs><rect width=\"1900\" height=\"980\" fill=\"#06131b\"\/><g font-family=\"Arial,Helvetica\"><text x=\"55\" y=\"64\" fill=\"#55dff7\" font-size=\"36\" font-weight=\"700\">Installed-cable PD acceptance decision flow<\/text><g stroke-width=\"6\"><rect x=\"110\" y=\"145\" width=\"450\" height=\"130\" rx=\"20\" fill=\"#0d1921\" stroke=\"#55dff7\"\/><rect x=\"725\" y=\"145\" width=\"450\" height=\"130\" rx=\"20\" fill=\"#0d1921\" stroke=\"#55dff7\"\/><rect x=\"1340\" y=\"145\" width=\"450\" height=\"130\" rx=\"20\" fill=\"#0d1921\" stroke=\"#55dff7\"\/><rect x=\"110\" y=\"410\" width=\"450\" height=\"130\" rx=\"20\" fill=\"#0d1921\" stroke=\"#f0c865\"\/><rect x=\"725\" y=\"410\" width=\"450\" height=\"130\" rx=\"20\" fill=\"#0d1921\" stroke=\"#f0c865\"\/><rect x=\"1340\" y=\"410\" width=\"450\" height=\"130\" rx=\"20\" fill=\"#0d1921\" stroke=\"#f0c865\"\/><\/g><g fill=\"#e8f3f5\" font-size=\"23\" text-anchor=\"middle\"><text x=\"335\" y=\"198\">Method + voltage<\/text><text x=\"335\" y=\"235\">match specification?<\/text><text x=\"950\" y=\"198\">Sensitivity proven<\/text><text x=\"950\" y=\"235\">at relevant locations?<\/text><text x=\"1565\" y=\"198\">Withstand completed<\/text><text x=\"1565\" y=\"235\">without failure?<\/text><text x=\"335\" y=\"463\">Defect-related PD<\/text><text x=\"335\" y=\"500\">repeatable and localized?<\/text><text x=\"950\" y=\"463\">PD at\/below U\u2080 or<\/text><text x=\"950\" y=\"500\">PDEV \u2264 U\u2080?<\/text><text x=\"1565\" y=\"463\">Project margin, PRPD<\/text><text x=\"1565\" y=\"500\">and trend acceptable?<\/text><\/g><g fill=\"none\" stroke=\"#d9edf0\" stroke-width=\"7\" marker-end=\"url(#a4)\"><path d=\"M560 210H710\"\/><path d=\"M1175 210H1325\"\/><path d=\"M1565 275V390\"\/><path d=\"M1340 475H1190\"\/><path d=\"M725 475H575\"\/><\/g><rect x=\"140\" y=\"720\" width=\"430\" height=\"140\" rx=\"24\" fill=\"#071821\" stroke=\"#ff9297\" stroke-width=\"7\"\/><text x=\"355\" y=\"780\" fill=\"#ff9297\" font-size=\"34\" font-weight=\"700\" text-anchor=\"middle\">FAIL \/ REWORK<\/text><text x=\"355\" y=\"824\" fill=\"#e8f3f5\" font-size=\"20\" text-anchor=\"middle\">Active defect or withstand failure<\/text><rect x=\"735\" y=\"720\" width=\"430\" height=\"140\" rx=\"24\" fill=\"#071821\" stroke=\"#f0c865\" stroke-width=\"7\"\/><text x=\"950\" y=\"780\" fill=\"#f0c865\" font-size=\"34\" font-weight=\"700\" text-anchor=\"middle\">HOLD<\/text><text x=\"950\" y=\"824\" fill=\"#e8f3f5\" font-size=\"20\" text-anchor=\"middle\">Unresolved source or margin<\/text><rect x=\"1330\" y=\"720\" width=\"430\" height=\"140\" rx=\"24\" fill=\"#071821\" stroke=\"#a6ded9\" stroke-width=\"7\"\/><text x=\"1545\" y=\"780\" fill=\"#a6ded9\" font-size=\"34\" font-weight=\"700\" text-anchor=\"middle\">PASS<\/text><text x=\"1545\" y=\"824\" fill=\"#e8f3f5\" font-size=\"20\" text-anchor=\"middle\">All evidence gates satisfied<\/text><path d=\"M950 540V700\" stroke=\"#d9edf0\" stroke-width=\"6\" marker-end=\"url(#a4)\"\/><path d=\"M1565 540V700\" stroke=\"#d9edf0\" stroke-width=\"6\" marker-end=\"url(#a4)\"\/><path d=\"M335 540V700\" stroke=\"#d9edf0\" stroke-width=\"6\" marker-end=\"url(#a4)\"\/><\/g><\/svg><div class=\"svg-caption\">Figure 4 \u2014 A numerical amplitude is only one gate in the final decision.<\/div><\/div>\n\n<section id=\"report\"><h2>What the final acceptance report must contain<\/h2><div class=\"scroll\"><table><caption>Minimum report record<\/caption><thead><tr><th>Category<\/th><th>Required fields<\/th><th>Why it matters<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">Asset identity<\/td><td>Circuit ID, cable manufacturer\/type, voltage, conductor size, insulation, route length, drum and accessory serial\/lot references.<\/td><td>Connects the result to the installed asset.<\/td><\/tr><tr><td class=\"key\">Circuit topology<\/td><td>Lengths, joint positions, terminations, link boxes, grounding and cross-bonding state.<\/td><td>Enables defensible localization and future comparison.<\/td><\/tr><tr><td class=\"key\">Test source<\/td><td>Waveform, frequency, voltage measurement, ramp, dwell, duration and protection\/stop settings.<\/td><td>Defines the electrical stress actually applied.<\/td><\/tr><tr><td class=\"key\">Measurement chain<\/td><td>Coupler\/sensor, acquisition instrument, bandwidth, filters, gain, sampling and synchronization.<\/td><td>Determines comparability and detection limits.<\/td><\/tr><tr><td class=\"key\">Sensitivity<\/td><td>Calibrator\/reference, injection points, recovered signals, noise floor and pre\/post verification.<\/td><td>Proves the acceptance threshold was observable.<\/td><\/tr><tr><td class=\"key\">PD data<\/td><td>q<sub>IEC<\/sub> or stated alternative unit, pulse rate, PRPD, PDIV, PDEV, location, polarity and time trend at every voltage step.<\/td><td>Supports source classification and risk assessment.<\/td><\/tr><tr><td class=\"key\">Disposition<\/td><td>Each cluster labeled cable, joint, termination, external, interference or unresolved; final Pass\/Hold\/Fail rationale.<\/td><td>Prevents a single peak value from replacing engineering judgment.<\/td><\/tr><tr><td class=\"key\">Raw evidence<\/td><td>Native data, screenshots, calibration files, photos, environmental conditions and signatures.<\/td><td>Allows independent audit and future baseline comparison.<\/td><\/tr><\/tbody><\/table><\/div><\/section>\n\n<section id=\"specification\"><h2>Model acceptance clauses for a procurement or commissioning specification<\/h2><div class=\"formula\">1. Scope\nThe test shall include the complete installed shielded cable system, including cable sections, joints, terminations and bonding interfaces identified on the approved circuit schedule.\n\n2. Method\nThe approved test waveform, frequency, voltage steps, maximum voltage, dwell and withstand duration shall be stated. Method substitution requires written engineering approval.\n\n3. Sensitivity\nBefore and after voltage application, the contractor shall demonstrate detection of the contractual reference signal at every relevant evaluation location. Failure to demonstrate the required sensitivity makes the result invalid.\n\n4. PD acceptance\nNo repeatable, defect-related and localized PD attributable to the installed cable system shall be present at the specified acceptance voltage above the demonstrated detection sensitivity.\n\n5. Operating-voltage rule\nAny repeatable cable, joint or termination PD that initiates or persists at or below U\u2080 shall be classified as nonconforming. PDEV shall exceed U\u2080 and any additional project margin stated in the data sheet.\n\n6. Source discrimination\nExternal corona and electromagnetic interference may be excluded only when supported by phase-resolved, time-correlated, multi-sensor, optical\/acoustic or other documented evidence.\n\n7. Deliverables\nThe report shall include PDIV, PDEV, magnitude\/unit definition, pulse rate, PRPD, location, voltage history, noise, sensitivity evidence, raw data and disposition of every cluster.\n\n8. Retest\nAfter repair or accessory replacement, the entire agreed acceptance sequence shall be repeated and linked to the original nonconformance record.<\/div>\n<p class=\"note\">The owner should add a project-specific PDEV margin, numerical sensitivity target and test-voltage schedule only after confirming the cable class, accessory standards, circuit length, test method and achievable noise floor.<\/p><\/section>\n\n<section id=\"applications\"><h2>Applying the criteria to high-consequence cable systems<\/h2><div class=\"scroll\"><table><caption>Application-focused acceptance priorities<\/caption><thead><tr><th>System<\/th><th>Commissioning risk<\/th><th>PD acceptance emphasis<\/th><\/tr><\/thead><tbody><tr><td class=\"key\">Ship-to-shore crane supply<\/td><td>Long feeder routes, vibration, joints near moving structures and high interruption cost.<\/td><td>Joint localization, remote sensitivity, termination corona control and baseline retention.<\/td><\/tr><tr><td class=\"key\">RTG\/RMG crane distribution<\/td><td>Power-electronic noise, grounding complexity and compact equipment rooms.<\/td><td>Reference sensors, source separation and simultaneous multi-channel acquisition.<\/td><\/tr><tr><td class=\"key\">Mining equipment feeder<\/td><td>Mechanical damage, moisture, contamination and difficult accessory access.<\/td><td>Pre-test inspection, section-by-section sensitivity and strict PD-at-U<sub>0<\/sub> rejection.<\/td><\/tr><tr><td class=\"key\">Conveyor system<\/td><td>Long distributed routes and many transitions or joints.<\/td><td>Accurate topology, reflection mapping and clear blind-zone disclosure.<\/td><\/tr><tr><td class=\"key\">Industrial process plant<\/td><td>Continuous-process consequences and multiple interference sources.<\/td><td>Coordinated outage, low-noise test window and auditable Hold criteria.<\/td><\/tr><tr><td class=\"key\">Critical auxiliary power<\/td><td>Failure can disable protection, cooling or safe shutdown functions.<\/td><td>Conservative PDEV margin, independent review and complete raw-data archive.<\/td><\/tr><\/tbody><\/table><\/div>\n<div class=\"box\"><h3>Feichun Cable engineering and compliance boundary<\/h3><p>Engineered for maximum safety in demanding environments, our cable systems comply with global standards including ATEX, IECEx, VDE, CE, UKCA, EAC, and the Russian Fire Safety Certificate. They are the trusted choice for heavy-duty mining equipment, ship-to-shore cranes, RTG\/RMG cranes, and conveyor systems where high reliability is non-negotiable.<\/p><p class=\"small\">Certificate applicability must be verified for the exact product, manufacturing site, certificate number, validity period and intended project. A partial-discharge commissioning result evaluates the tested installed insulation system under the stated procedure; it does not by itself establish any listed product or market certification.<\/p><\/div><\/section>\n\n<section id=\"faq\"><h2>Frequently asked questions and RFQ inputs<\/h2><div class=\"grid\"><div class=\"box\"><h3>Is 10 pC the normal field pass limit?<\/h3><p>No universal rule makes 10 pC valid for every installed circuit. It can be a contractual limit only when the measurement definition and end-to-end sensitivity at relevant locations are demonstrated.<\/p><\/div><div class=\"box\"><h3>Does zero displayed pC prove a defect-free circuit?<\/h3><p>No. It proves only that the instrument displayed no activity above its effective sensitivity and processing threshold under the test conditions.<\/p><\/div><div class=\"box\"><h3>Should any PD above U<sub>0<\/sub> fail?<\/h3><p>Not automatically. Repeatable localized activity above U<sub>0<\/sub> requires review against the specified PDEV margin, defect type, amplitude, repetition, stability and applied test stress.<\/p><\/div><div class=\"box\"><h3>What is the clearest failure condition?<\/h3><p>Repeatable, localized internal or accessory PD at or below U<sub>0<\/sub>, especially when PDEV is at or below U<sub>0<\/sub> or activity grows with voltage.<\/p><\/div><div class=\"box\"><h3>Can online readings be compared with factory pC?<\/h3><p>Usually not directly. Online HFCT or UHF measurements may not satisfy the same apparent-charge definition, bandwidth or calibration geometry as a factory IEC 60270 circuit.<\/p><\/div><div class=\"box\"><h3>Does a withstand pass override PD findings?<\/h3><p>No. Withstand and PD diagnostics answer different questions. A circuit can survive the test duration while containing an active defect that warrants rework.<\/p><\/div><\/div>\n<div class=\"formula\">Minimum PD acceptance RFQ data\nCable system: rated voltage \u00b7 U\u2080 \u00b7 insulation \u00b7 conductor \u00b7 screen \u00b7 length \u00b7 joint count \u00b7 termination type\nTopology: joint distances \u00b7 bonding\/cross-bonding \u00b7 link boxes \u00b7 parallel circuits \u00b7 accessible sensor points\nTest method: power-frequency\/resonant \u00b7 VLF \u00b7 DAC \u00b7 online \u00b7 monitored withstand\nVoltage schedule: ramp \u00b7 steps \u00b7 dwell \u00b7 test voltage \u00b7 duration \u00b7 descending U\u2080 dwell\nAcceptance: sensitivity target \u00b7 required locations \u00b7 PDEV margin \u00b7 PD-at-U\u2080 rule \u00b7 stop criteria\nMeasurement: IEC 60270 or non-conventional sensor \u00b7 bandwidth \u00b7 synchronization \u00b7 localization method\nEnvironment: temperature \u00b7 humidity \u00b7 interference survey \u00b7 adjacent energized equipment\nDocuments: factory PD reports \u00b7 accessory standards \u00b7 installation records \u00b7 raw data format \u00b7 baseline retention<\/div><\/section>\n\n<section id=\"sources\"><h2>Technical sources and argument support<\/h2><ul class=\"source-list\"><li><a href=\"https:\/\/standards.ieee.org\/ieee\/400.3\/5316\/\" target=\"_blank\" rel=\"nofollow noopener\">IEEE 400.3-2022<\/a> \u2014 active guide covering online or externally energized PD detection, measurement and location on new or service-aged installed shielded cable systems, including joints and terminations.<\/li><li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/65087\" target=\"_blank\" rel=\"nofollow noopener\">IEC 60270:2025<\/a> \u2014 current charge-based PD measurement standard covering quantities, circuits, frequency ranges, calibration, instruments, procedure and interference discrimination.<\/li><li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/114698\" target=\"_blank\" rel=\"nofollow noopener\">IEC 60502-2:2014+A1:2024\/COR1:2026<\/a> \u2014 current consolidated\/corrected product-standard route for extruded-insulation cables from 6 kV to 30 kV rated voltage classes.<\/li><li><a href=\"https:\/\/media.faberkabel.de\/differences-vde-iec.pdf\" target=\"_blank\" rel=\"nofollow noopener\">Technical comparison of IEC 60502-2 and the corresponding VDE cable requirements<\/a> \u2014 concise tabulation supporting the cited 10 pC routine-test and 5 pC type-test reference levels at 1.73 U<sub>0<\/sub>; the governing standard remains the controlled IEC text.<\/li><li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/85973\" target=\"_blank\" rel=\"nofollow noopener\">IEC 60840:2020+A1:2023<\/a> \u2014 cable systems above 30 kV up to 150 kV, with a correction issued in 2025.<\/li><li><a href=\"https:\/\/webstore.iec.ch\/en\/publication\/66951\" target=\"_blank\" rel=\"nofollow noopener\">IEC 62067:2022<\/a> \u2014 cable systems above 150 kV up to 500 kV.<\/li><li><a href=\"https:\/\/standards.ieee.org\/ieee\/404\/10721\/\" target=\"_blank\" rel=\"nofollow noopener\">IEEE 404-2022<\/a> and <a href=\"https:\/\/standards.ieee.org\/ieee\/48\/6208\/\" target=\"_blank\" rel=\"nofollow noopener\">IEEE 48-2020<\/a> \u2014 test requirements and procedures for shielded cable joints and terminations.<\/li><li><a href=\"https:\/\/standards.ieee.org\/ieee\/400.4\/11418\/\" target=\"_blank\" rel=\"nofollow noopener\">IEEE 400.4<\/a> \u2014 field testing of shielded cable systems using damped alternating current.<\/li><li><a href=\"https:\/\/neta.netaworld.org\/netassa\/ecssashop.show_product_detail?p_product_serno=582\" target=\"_blank\" rel=\"nofollow noopener\">ANSI\/NETA ATS-2025<\/a> \u2014 acceptance-testing framework for initial energization, including medium-voltage cable acceptance tables and cable reliability guidance.<\/li><li><a href=\"https:\/\/netaworldjournal.org\/2022\/11\/aaronaguirre\/cover-story\/measuring-partial-discharge-on-medium-voltage-cables\/\" target=\"_blank\" rel=\"nofollow noopener\">NETA World \u2014 Measuring Partial Discharge on Medium-Voltage Cables<\/a> \u2014 practical discussion of test-voltage ranges, PDIV\/PDEV and the absence of established universal field thresholds.<\/li><li><a href=\"https:\/\/cigre.cz\/dokumenty_komise\/d1\/WG%20D1.37_TB_Final.pdf\" target=\"_blank\" rel=\"nofollow noopener\">CIGRE Technical Brochure 662<\/a> \u2014 guidance on conventional and unconventional PD detection and the importance of measurement method, calibration and source discrimination.<\/li><\/ul><p class=\"small\">This article distinguishes normative product limits from common engineering practice. Standards are copyrighted; the article summarizes public scope and engineering implications rather than reproducing controlled procedures. Test voltage, duration, sensitivity and final acceptance must be established from the applicable full standards, the owner\u2019s specification, manufacturer instructions and the approved cable-system design.<\/p><\/section><\/main>\n\n<footer><div class=\"wrap\"><div class=\"footer-grid\"><div><h2>Feichun Cable \u00b7 Partial-discharge acceptance engineering support<\/h2><p>Provide the cable-system voltage, length, accessory map, test waveform, acceptance voltage, sensitivity target, PDEV margin and required documentation so the test plan can be converted into auditable Pass \/ Hold \/ Fail clauses.<\/p><div class=\"contact\"><div><strong>Phone<\/strong><br>+86 13855123218<\/div><div><strong>Technical email<\/strong><br><a href=\"mailto:Tech@feichuncables.com\">Tech@feichuncables.com<\/a><\/div><\/div><\/div><div><h3>Feichun Cable<\/h3><p>\u98de\u7eaf\u7535\u7f06<\/p><p>Power cable \u00b7 Mining cable \u00b7 Crane cable \u00b7 Cable-system engineering<\/p><p class=\"small\">No additional contacts or contact details have been added.<\/p><\/div><\/div><\/div><\/footer><\/body><\/html>\n","protected":false},"excerpt":{"rendered":"For a new installed cable system, the most common defensible criterion is: no repeatable, defect-related, localized partial discharge attributable to the cable, a joint or a termination at the specified commissioning voltage, above a detection sensitivity that has been demonstrated for the relevant location. PD that persists at or below normal phase-to-ground operating voltage U0 is normally a reject or rework condition.","protected":false},"author":1,"featured_media":26031,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"csco_singular_sidebar":"left","csco_page_header_type":"title","csco_page_load_nextpost":"","footnotes":""},"categories":[66],"tags":[16],"class_list":["post-26030","post","type-post","status-publish","format-standard","has-post-thumbnail","category-common-problems-encountered-in-cable-applications","tag-din-vde-0250","cs-entry"],"_links":{"self":[{"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/posts\/26030","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/comments?post=26030"}],"version-history":[{"count":2,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/posts\/26030\/revisions"}],"predecessor-version":[{"id":26033,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/posts\/26030\/revisions\/26033"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/media\/26031"}],"wp:attachment":[{"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/media?parent=26030"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/categories?post=26030"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/tags?post=26030"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

{"id":26030,"date":"2026-08-10T09:51:32","date_gmt":"2026-08-10T01:51:32","guid":{"rendered":"https:\/\/feichuncables.com\/blog\/?p=26030"},"modified":"2026-08-10T09:56:27","modified_gmt":"2026-08-10T01:56:27","slug":"what-acceptance-criteria-or-pass-fail-thresholds-are-commonly-used-for-partial-discharge-measurements-on-new-cable-installations","status":"publish","type":"post","link":"https:\/\/feichuncables.com\/blog\/what-acceptance-criteria-or-pass-fail-thresholds-are-commonly-used-for-partial-discharge-measurements-on-new-cable-installations\/","title":{"rendered":"What Acceptance Criteria or Pass\/Fail Thresholds Are Commonly Used for Partial Discharge Measurements on New Cable Installations?"},"content":{"rendered":"\n