750kV Partial Discharge-Free AC Withstand Voltage Test System
Products Description
The MOEORW-WPB268 750kV Partial Discharge-Free AC Withstand Voltage Test System is a professional-grade testing solution designed for both state-of-the-art high-voltage laboratories and demanding on-site field testing environments.
Fully compliant with IEC 60270 and GB7354 standards, this heavy-duty system serves as a dependable high-voltage power source to perform safe, accurate, and stable AC withstand voltage testing and partial discharge (PD) measurements on critical grid components.
product Parameter (specification)
The following key technical parameters are verified through full-load aging tests prior to shipment, ensuring consistent performance across every unit.
| Parameter | Specification | Remarks |
|---|---|---|
| Rated Input Voltage | Three-phase 400V ± 10%, 50Hz | Leakage protector must be bypassed at power source |
| Rated Output Power | Single-phase 260kW | Rated as 260kW (not 260kVA), emphasizing active power capability |
| Output Frequency Range | 20Hz – 300Hz, continuously adjustable | Covers low-frequency cable and high-frequency GIS test requirements |
| Rated Output Voltage | 0 – 350V, continuously adjustable | Adaptable to all voltage levels via excitation transformer ratio adjustment |
| Rated Output Current | 0 – 742A, continuously adjustable | High current capacity meets large-capacity test object requirements |
| Frequency Stability | ≤ 0.05% | Ensures resonance point stability and consistent voltage output |
| Voltage Instability | ≤ 1.0% | High-precision regulation prevents over-voltage or under-voltage on test object |
| Nonlinear Distortion | ≤ 1% | Superior to industry standard (standard requires <3%) |
| Partial Discharge Level | ≤ 10pC (measured at HV side of excitation transformer) | Meets IEC 60270 partial discharge testing standard |
| Cooling Method | Forced air cooling | Ducted design prevents overheating during extended operation |
| Noise Level | < 85dB | Lower than comparable products, improving on-site working environment |
| Dimensions | 1800 × 800 × 1650 mm | Compact footprint suitable for mobile test vehicle installation |
| Total Weight | 1300kg | Over 50% weight reduction compared to generator sets |
Key Advantages
Ultra-Low Background PD (≤10pC) for High-Precision Testing
The system guarantees an overall partial discharge level of ≤10pC at rated high voltage. Driven by pure sine wave linear power amplification (waveform distortion ≤1%), it eliminates harmonic noise and square-wave shaping interference. With a corona-free design and precise single-point grounding, it ensures true, uncorrupted PD measurement results compliant with IEC 60270.
Series Resonance Technology for Unmatched Power Efficiency
By leveraging the series resonance step-up principle, the system multiplies the excitation voltage by a quality factor (Q value of 30–50). The required power source capacity is slashed to just 1/Q of traditional test methods. This allows a standard 380V/50Hz mains supply to easily drive 750kV high-voltage tests on large-capacity capacitive loads like GIS and long-run cables.
Millisecond-Level Hardware Interlock Safety Protections
Engineered with 6 independent hardware-level safety mechanisms-including breakdown, overvoltage, output short-circuit, zero-start, bridge-arm amplification, and power curve protection. Utilizing electrical hard-wired interlocks, the system cuts off main power in milliseconds upon fault detection. It maintains a constant energy discharge path, completely preventing forced overvoltage during power failures.
Fiber-Optic Isolated Controls for Absolute Operator Safety
The control console and the variable frequency power supply communicate exclusively via fiber-optic cables. All high-voltage feedback and measurement signals are transmitted through isolated optical links. With zero electrical connection between the high-voltage circuit and the operator panel, high-voltage intrusion risks are 100% eliminated.
Product Application
Power Transformers (Up to 750kV)
Induced voltage withstand tests (fully compliant with GB/T 1094.3 / IEC 60076-3).
High-precision partial discharge (PD) measurements (per GB7354 / IEC 60270).
Substation & Switchgear Equipment (110kV – 750kV)
AC withstand voltage testing for GIS (Gas Insulated Switchgear) and disconnectors.
Power-frequency withstand voltage testing for circuit breakers, insulators, and bushings.
Cables & Capacitive Loads
AC withstand voltage tests on high-voltage and extra-high-voltage (EHV XLPE) power cables.
Insulation testing for other large-capacity capacitive electrical equipment.
Generators & Large Grounding Grids
Power-frequency withstand voltage testing for large utility-scale generator units.
Serves as a high-power variable frequency power source for extensive grounding grid testing.
Product Selection and Configuration Guide
Selecting the correct excitation transformer tap and winding combination is critical to overall system performance. An inappropriate setting forces the variable-frequency power supply into a low-voltage, high-current operating zone. This can trigger power-curve protection trips or accelerate thermal wear on the power transistors.
1. Reference Tap-Matching Matrix (Transformer Induced Hipot & PD Measurements)
| DUT Voltage Class | Excitation‑Transformer HV Tap Deployed | Intermediate‑stage Transformation Ratio | Maximum Attainable Test Voltage |
|---|---|---|---|
| 110 kV Transformer | 35 kV Winding | K = 70/0.36 = 194.5 | 257.6 kV (Partial‑Discharge measurement) |
| 220 kV Transformer | 35 kV Winding | K = 70/0.4 = 175 | 231.9 kV (Withstand‑voltage test) |
| 220 kV Transformer | 20 kV Winding | K = 35/0.32 = 109.4 | 257 kV (Partial‑Discharge measurement) |
| 550 kV Transformer | 10 kV Winding | K = 35/0.66 = 53 | 586.3 kV (Withstand‑voltage test) |
2. Flexible Winding Reconfiguration Options
Low-Voltage (LV) Windings
Parallel Connection: Delivers the full 260 kVA rated capacity at an elevated input current. Ideal for high-current, low-voltage excitation scenarios.
Series Connection: Maintains the 260 kVA apparent power while cutting the input current magnitude in half. Best suited for higher input voltage demands.
High-Voltage (HV) Windings
Standard Parallel Connection: Parallels same-rating windings for traditional single-ended, ground-referenced high-voltage output tasks.
Bipolar Symmetrical Output: Configures positive/negative floating outputs relative to the ground. This is specifically dedicated to transformer induced voltage tests requiring balanced, bidirectional excitation.
3. Core Principles for Tap Selection & Optimization
- Maintain Optimal Voltage Window: Always stabilize the variable-frequency source output voltage within the 300 V – 350 V window. This minimizes output current magnitude and limits transistor thermal dissipation. Continuous operation below 300 V amplifies transistor power losses and may trigger protective trips.
- Voltage Boosting Strategy: If a single-winding configuration fails to reach the target test voltage, reconfigure the low-voltage side into a series connection to elevate the excitation input voltage and suppress loop current.
- Reactive Power Limitation: When testing high-capacitance specimens (such as extra-long cables or large-capacity power transformers), verify that the total reactive power draw does not exceed 450 kVA under pure reactive load operation.
Products Description
This device is strictly designed, manufactured, and tested in accordance with the following international and national standards, ensuring product compliance and meeting the access requirements of domestic and international power test institutions:
| Standard No. | Standard Title | Relevant Clauses |
|---|---|---|
| IEC 60270 | High-voltage test techniques – Partial discharge measurements | PD level ≤10pC; background noise verification |
| IEC 60060-1 | High-voltage test techniques – General definitions and test requirements | Waveform distortion (<3%), voltage stability (±1%) |
| IEC 60060-3 | High-voltage test techniques – Definitions and requirements for on-site testing | Applicability for field test procedures |
| DL/T 848.3 | General technical specification for high-voltage test devices – Part 3: Partial discharge-free test transformers | PD level, temperature rise, insulation level verification |
| DL/T 596 | Preventive test code for electric power equipment | Test method applicability for transformers, GIS, cables |
| GB/T 16927.1 | High-voltage test techniques – Part 1: General definitions and test requirements | Withstand voltage test procedures and acceptance criteria |
| GB/T 1094.3 | Power transformers – Part 3: Insulation levels, dielectric tests and external clearances in air | Induced voltage withstand and partial discharge test methods |
| JB/T 9641 | General technical specification for test transformers | Construction, cooling, and rating requirements |
Compliance Verification:
Each device undergoes the following compliance verifications prior to shipment:
Type Test Report: Complete type test documentation including partial discharge test curves, temperature rise records, short-circuit impedance measurement, and insulation level verification. Available upon request.
Factory Test Report: Individual test records for each delivered unit, including protection action verification, output waveform distortion measurement, and frequency stability validation.
Third-Party Certification: Optional third-party witnessed testing available at additional cost for projects requiring independent verification.
Product Traceability:
Every device is assigned a unique serial number engraved on the nameplate. Using this serial number, customers can:
Access the original factory test records through our online verification portal
Verify calibration dates and traceability to national standards
Retrieve historical service records and software version information
Confirm warranty status and eligibility for extended service plans
Cross-Border Compliance:
For international shipments, the device is designed to accommodate variations in local grid conditions:
Rated input voltage accommodates 400V ±10%, covering most 380V–440V industrial grids worldwide
Frequency range (20Hz–300Hz) meets test requirements across 50Hz and 60Hz reference systems
Transformer tap configurations support both European (380V) and North American (480V) primary voltage standards
CE marking available upon request for European market access
Recommended Periodic Compliance Checks:
To maintain ongoing compliance with industry standards, we recommend the following periodic checks:
| Check Item | Recommended Frequency | Standard Reference |
|---|---|---|
| Partial discharge background check | Annually or after major transport | IEC 60270 |
| Protection action verification | Annually or after any protection trip | Factory procedure |
| Output waveform distortion measurement | Every 2 years | IEC 60060-1 |
| Cooling system airflow verification | Every 6 months | Factory procedure |
| Grounding continuity check | Before each test series | Site safety regulation |
Standard Inclusions
| Accessory Name | Model / Specification | Description |
|---|---|---|
| Variable Frequency Power Supply Cabinet | MOEORW-WPB268-260 | Main unit, 260kW output, 20–300Hz, fiber-optic control |
| Excitation Transformer | MELB1109Y-260 | 260kVA, multi-tap HV winding (8 bushings), supports multiple ratio combinations |
| Multi-functional Intelligent Peak Voltmeter | METRF750 | 7" touchscreen, data logging (CSV export), battery-powered, galvanic isolation |
| Fiber-Optic Communication Cable | Custom length | Physical isolation between HV side and control console |
| Dedicated Input / Output Cables | Matched set | Three-phase input cable and interconnection cable to excitation transformer |
| Grounding Cable | Matched set | For single-point grounding of the system |
| Aluminum Flight Case | Custom | For control console and voltmeter, with shockproof foam |
FAQ
Q1: What is the actual internal partial discharge (PD) level of the MOEORW-WPB268 system itself at full 750kV load?
A: The inherent partial discharge level of our system is strictly guaranteed to be ≤10pC (and can be customized down to ≤2pC - 5pC depending on specific configurations) at the maximum rated 750kV voltage. Powered by pure sine wave linear amplification with a waveform distortion rate of ≤1%, the system fundamentally eliminates high-frequency noise, ensuring high-precision, uncorrupted measurement results compliant with IEC 60270.
Q2: Can this 750kV system be powered by a standard site grid, or does it require a dedicated high-capacity substation?
A: It can run on a standard three-phase 380V/50Hz (or 415V/60Hz) mains supply. Thanks to our series resonance design, the system's power source capacity requirement is slashed to only 1/Q (typically 1/30 to 1/50) of traditional test transformers. It multiplies the reactive power internally, meaning a low-voltage grid input of several hundred amperes is fully sufficient to generate the 750kV high voltage, solving the challenge of insufficient on-site power.
Q3: Does the system support both Induced Overvoltage (DVDF) and Separate-Source AC Withstand tests for transformers?
A: Yes, absolutely. The MOEORW-PB268 is a multi-functional system. By reconfiguring the excitation transformer's high-voltage windings into a bipolar symmetrical floating output, it provides the balanced bidirectional excitation required for transformer induced voltage withstand tests (per IEC 60076-3). When configured in standard parallel single-ended mode, it operates perfectly for standard AC withstand voltage testing on GIS, power cables, and bushings.
Q4: How does the system handle abrupt flashovers or breakdowns during a 750kV test? Will it damage the control console or PD detector?
A: The system is engineered with 6-fold hardware-level interlock protections (with millisecond-level response times) and 100% fiber-optic signal isolation. There is no electrical wire connection between the high-voltage testing loop and the low-voltage control console. In the event of a test object breakdown, the hard-wired interlock cuts off the main power instantly, and the dedicated overvoltage energy discharge path safely grounds the residual charge, ensuring absolute safety for operators, detectors, and the system itself.
Request a Technical Proposal & Quote
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