Shanghai DEMIKS Power Technology Co., Ltd. has recently completed the turnkey delivery of a full-set partial discharge shielding laboratory project for Hunan HD Electric Equipment Co., Ltd. The whole project includes an electromagnetic shielding partial discharge laboratory, DJF-124 10kVA/50kV partial discharge test system, power frequency partial discharge-free withstand voltage test equipment, as well as integrated high-voltage measurement & control software and hardware. The solution empowers Hunan HD Electric to conduct independent type tests such as partial discharge detection and AC withstand voltage test for box-type substations and high-voltage switchgears.
Project Introduction
Hunan HD Electric manufactures outdoor box transformers, ring main units and high-voltage switchgear. These power apparatus require strict partial discharge testing and PD-free power frequency withstand voltage tests. Previously, third-party testing brought long lead time and high costs. Building an in-house standardized high voltage PD laboratory became a core strategy for quality control. Demiks Power undertook the whole EPC scope:
- Construction of partial discharge shielding room (EMI shielding laboratory)
- DJF-124 AC partial discharge measuring system: PD-free testing transformer, coupling capacitor, isolation filter, automatic control console and partial discharge detector
- Integrated grounding system, high-voltage safety interlock, wiring, site commissioning and operator training. The system has finished joint debugging and is available for full-scale partial discharge test and power frequency withstand voltage test of high voltage switch-gears and outdoor box-type substations.
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Core Advantages of Partial Discharge Shielding Room
The partial discharge shielding laboratory is the fundamental infrastructure for high-precision partial discharge detection. External electromagnetic disturbance will cause fake PD signals and invalid test results. The shielding performance directly determines the measuring limit of your high voltage partial discharge test system.
- High electromagnetic shielding efficiency to suppress ambient noise Demiks PD shielding room adopts fully sealed metal shielding structure, optimized for power frequency magnetic field and RF interference in factories. It effectively isolates disturbance from inverters, overhead cables and communication signals, supporting pC-level partial discharge measurement and reliable PD-free withstand voltage test.
- Customized shielding door & shielding observation window Large motor-driven shielding sliding door allows integral loading of complete box-type substation and high-voltage switchgear without disassembling test samples. Shielded observation window with double-layer metal mesh enables external monitoring while preventing electromagnetic wave leakage.
- Power line filter system to block conducted interference All power cables entering the shielding chamber pass through professional EMI power filters. Conducted noise from grid is the major cause of high background partial discharge. Multi-stage filter units are equipped to maintain ultra-low background PD level.
Spacious layout for full-size power equipment testing Enough inner space and mobile transport platform support testing of intact ring main units and box transformers, so engineers can acquire real partial discharge characteristics under actual operating conditions.
Integrated high voltage safety protection High voltage interlock access control, sound-light alarm and emergency stop circuit are installed. The high voltage source will be automatically locked once shielding door opens, complying with international safety standards for high voltage laboratories.
Key Notes for Partial Discharge Shielding Laboratory Construction
Many high voltage equipment manufacturers encounter excessive background partial discharge after lab construction due to ignored technical details. Based on abundant engineering experience, DEMIKS Power summarizes critical construction guidelines:
- Select site far away from strong interference sources Avoid locations close to factory substations, frequency converters, welding machines, large motors and radio transmitters. Keep distance from heavy power cable trays.
- Independent frame for shielding enclosure The metal shielding shell requires self-support frame instead of directly attaching to building walls. All cable penetration openings must adopt wave-guide windows and shielded connectors to avoid electromagnetic leakage gaps.
- Separate grounding networks Distinguish shielding shell grounding, high voltage test working grounding and building safety grounding. Do not share grounding loops with high-power factory equipment.
- Pr-plan layout of high voltage components Arrange testing transformer, coupling capacitor and high voltage leads in advance to avoid sharp metal parts and floating potential which generate extra internal partial discharge.
- Reserve sufficient filtered power channels Prepare extra filtered power ports for future expansion of high voltage test instruments. Drilling holes afterward will damage shielding integrity.
- Carry out acceptance test after completion Both shielding effectiveness test and background partial discharge measurement are mandatory before putting the lab into service. Only with qualified background noise, the partial discharge test system and PD-free withstand voltage equipment can capture real PD signals from test objects.
Introduction of DJF-124 Partial Discharge Test System
The delivered DJF-124 partial discharge monitoring system integrates automatic voltage regulation, PD-free testing transformer and high-sensitivity PD acquisition unit. It supports synchronous power frequency withstand voltage test and real-time partial discharge monitoring, complying with GB/T 11022, GB 3906 standards. Widely used for type test and routine test of box substations, RMU, gas insulated switch-gear, instrument transformers and cable accessories.
About DEMIKS Power Technology Co., Ltd.
Shanghai DEMIKS Power Technology Co., Ltd. focuses on R&D of high voltage testing equipment, EPC of partial discharge shielding laboratories and customized high voltage testing solutions. Main products: Partial discharge detection system, power frequency PD-free withstand voltage tester, variable frequency series resonance system, lightning impulse generator, SF6 gas analyzer and partial discharge shielding room turnkey project. We serve high voltage switch manufacturers, transformer factories and power testing institutions domestically and overseas, delivering one-stop high voltage laboratory solutions for power equipment industry.
