Key keywords: partial discharge-free power frequency withstand voltage test device, partial discharge detector, gas-filled test transformer, 10kV ring main unit factory inspection, high-voltage complete set of equipment testing equipment, DEMIKS POWER high-voltage testing equipment, SF6 gas-filled switch-gear insulation testing, switch-gear partial discharge withstand voltage test.
Recently, Shanghai DEMIKS Power Technology Co., Ltd. (brand: DEMIKS POWER, website: www.demikspower.com ) and Shandong Langyun Electric Co., Ltd. reached a deep cooperation agreement on equipment procurement and technical services. A DJF series 10kVA/50kV intelligent partial discharge-free power frequency withstand voltage partial discharge comprehensive test system was officially delivered to Shandong Langyun Electric’s production and testing workshop and completed on-site commissioning and personnel training. The entire set of equipment has been fully put into the factory insulation performance testing of SF6 ring main units, environmentally friendly gas-insulated switch-gear, and solid-insulated switch-gear, completing the core hardware for the whole process quality inspection of medium and high voltage complete sets of power distribution equipment, greatly improving the standardization and digitalization level of Shandong Langyun Electric’s product factory testing, and providing authoritative testing data support for the company’s domestic and foreign market supply and type testing certification.
I. Background of the cooperating companies and the scenarios for cooperation implementation
Shanghai DEMIKS Power Technology Co., Ltd.
As a high-tech enterprise in China specializing in the R&D, production, and complete solution output of high-voltage insulation testing equipment, DEMIKS POWER has been deeply involved in the high-voltage testing field for many years. It provides one-stop high-voltage testing solutions to high-voltage complete equipment manufacturers, transformer manufacturers, power testing institutes, new energy booster stations, and rail transit electrical companies. Its main products cover a full range of power testing instruments, including partial discharge withstand voltage testing equipment, frequency converter series resonant devices, partial discharge detection systems, dielectric loss testers, switch characteristic testers, and SF6 gas detection equipment. The equipment complies with international and domestic standards such as GB/T 11022 and IEC 62271, supports Chinese and English operating interfaces and bilingual test report output, and is suitable for domestic power grid bidding and export inspection needs in North America, Southeast Asia, and Europe. It serves hundreds of high and low voltage complete electrical equipment manufacturing companies nationwide.
Shandong Langyun Electric Co., Ltd.
Located in Tai’an, Shandong, the company specializes in the R&D and production of 10kV SF6 gas-insulated ring main units, environmentally friendly fluorine-free gas-filled switch-gear, solid-insulated switchgear, and high-voltage complete distribution cabinets. Its products are widely used in municipal power distribution networks, residential power distribution, industrial parks, photovoltaic and wind power voltage boosting, and commercial complexes. The company possesses complete sheet metal processing and assembly production lines. Strictly adhering to the State Grid and China Southern Power Grid’s factory testing standards, a complete set of high-voltage insulation testing equipment is a mandatory qualification requirement for product compliance and third-party type testing certification. This procurement of the DEMIKS POWER partial discharge withstand voltage and partial discharge withstand voltage complete system will be used for the power frequency withstand voltage and partial discharge forced factory testing of each high-voltage switch-gear unit. On-site training was provided on the entire process, including equipment wiring, voltage boosting operation, partial discharge waveform acquisition, and report printing. The technical team accompanied the testing of samples throughout the process to verify the equipment’s testing accuracy and stability.
II. Detailed Explanation of the Practical Application of DEMIKS POWER Complete Set of Equipment in Shandong Langyun Electric
The DJF Intelligent Partial Discharge-Free Power Frequency Withstand Voltage and Partial Discharge Comprehensive Test System delivered this time is an integrated design by DEMIKS POWER. It corresponds to four sets of on-site equipment, and its five core units work together to complete two core insulation tests: gas-insulated switch-gear and ring main unit.
6.The intelligent partial discharge withstand voltage integrated control console is the central control unit of the entire system. It integrates a programmable voltage regulation and boosting module and a dual-channel partial discharge acquisition unit. Dual touchscreens display withstand voltage operating parameters and real-time partial discharge pulse wave-forms, respectively. Equipped with multiple safety protections including emergency stop, over-voltage, and over-current protection, it can automatically set the withstand voltage boosting rate and stabilization time. Upon test completion, it automatically reduces voltage, stores data, and prints test reports in both Chinese and English. Shandong Langyun Electric’s testing personnel can start the entire test with a single button on the control console, eliminating the need for individual equipment operation, reducing human error, and making it suitable for batch switch-gear factory assembly line testing.
7.the 10kVA/50kV gas-insulated partial discharge-free test transformer adopts an SF6 gas-insulated structure. The equipment’s own partial discharge is ≤5pC, which will not cause stray discharge to interfere with the test results. It can stably output a maximum of 50kV power frequency high voltage, meeting the 42kV power frequency withstand voltage test standard for 10kV switch-gear. Unlike traditional oil-immersed transformers, it has the advantages of small size, low partial discharge, maintenance-free operation, and no leakage, making it suitable for long-term continuous batch testing conditions in workshops.
8.A 50kV partial discharge-free current-limiting protection resistor is connected in series in the high-voltage output circuit. When the insulation of the switch-gear under test breaks down, it limits the large short-circuit impact current, protects the test transformer, coupling capacitor and the entire testing system, avoids equipment damage caused by a single breakdown, extends the service life of the equipment, and ensures the safety of workshop test operations.
9.The 50kV/100pF high-voltage coupling capacitor is a key component for partial discharge signal acquisition. It accurately couples and extracts the discharge pulse signal generated by insulation defects inside the switch-gear, and transmits it to the control panel partial discharge module to calculate the discharge quantity (pC) value. It accurately identifies hidden insulation defects such as bubbles, gaps, and impurities inside the cabinet, and is an indispensable core component for partial discharge detection of gas-filled switch-gear.
10.The isolation filter voltage regulator transformer isolates the power grid harmonics and noise interference generated by welding machines, CNC sheet metal equipment, and frequency converters in the workshop, purifies the input power supply, ensures high sensitivity of partial discharge detection, eliminates external electromagnetic interference that may lead to misjudgment of partial discharge data, and ensures accurate and reliable test results.
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The equipment has two core testing functions (compatible with the production of gas-insulated switch-gear and ring main units).
3.The power frequency AC withstand voltage test applies a 42kV power frequency high voltage to the 10kV high voltage switch-gear according to national standards and lasts for 5 minutes to test the overall insulation strength of the cabinet and identify obvious defects such as insulation breakdown and insufficient creepage distance. Products that fail the withstand voltage test are prohibited from leaving the factory.
4.Partial discharge testing continuously monitors the partial discharge level of the cabinet under rated operating voltage. The national standard requires the partial discharge value of the entire gas-insulated switch-gear to be ≤20pC. If the partial discharge exceeds the standard, it indicates that there are minor defects in the internal insulation. Long-term operation will lead to overheating, insulation aging, and cabinet breakdown and explosion risks. Through the waveform visualization function of the DEMIKS partial discharge system, the defect location can be quickly located, guiding the workshop to rework and rectify.
III. List of Essential High-Voltage Testing Equipment for the 10kV High-Voltage Switch-gear Industry (with examples from the DEMIKS POWER website www.demikspower.com )
For manufacturers of ring main units, gas-insulated switch-gear, and high-voltage complete sets, such as Shandong Langyun Electric, a complete quality inspection workshop needs to be equipped with five major series of high-voltage testing equipment: insulation withstand voltage testing, partial discharge testing, switch characteristic testing, SF6 gas testing, and general electrical testing. Complete parameters and complete solutions for all categories can be found on the DEMIKS POWER website.
1. Core equipment for insulation withstand voltage and partial discharge testing (the main category of this procurement)
DJF series power frequency withstand voltage and partial discharge integrated test system: This is the main model deployed in Shandong Lang-yun, which can perform both withstand voltage and partial discharge tests and is suitable for testing 10kV gas-insulated switch-gear and ring main unit.
XZ series variable frequency series resonant withstand voltage test device: The official website mainly promotes withstand voltage testing of long cables, GIS, and large instrument transformers, and it is suitable for factory testing of long-distance 10kV power cables;
YDQ gas-filled test transformer single set equipment: a lightweight withstand voltage solution for small complete sets of equipment, used in conjunction with an independent partial discharge instrument.
2. High-voltage switch mechanical characteristics and circuit testing equipment
High-voltage switch mechanical characteristic tester: detects the opening and closing time, stroke, and bounce parameters of vacuum circuit breakers and load switches, and verifies the reliability of the switch mechanical structure;
Loop resistance tester: measures the contact resistance of the main circuit of the switch-gear to check for potential overheating caused by poor contact of busbars and contacts;
Switch-gear energization comprehensive test bench: completes full-function energization testing of secondary circuit on/off, protection linkage, and transformer ratio and polarity.
3. SF6 gas switch-gear dedicated gas detection equipment (essential for Langyun Electric’s gas switch-gear production line)
SF6 moisture detector: detects the moisture content of SF6 gas inside the gas-filled cabinet. Excessive moisture will accelerate insulation aging.
SF6 gas leak detector: detects leaks in cabinet welds and flange seals to prevent leakage of insulating gas;
SF6 gas recovery and charging device: When the cabinet is repaired or scrapped, SF6 medium is recovered and reused, which complies with environmental protection production standards.
4. Insulating media and general high-voltage testing instruments
Fully automatic dielectric loss tester (dielectric loss meter): detects the dielectric loss factor of bushings and transformer insulation, and assesses the degree of insulation aging;
Insulation resistance tester, DC high voltage generator: spot check of DC withstand voltage and insulation resistance of busbars, cables, and surge arresters;
Inductive withstand voltage test device: Inductive withstand voltage test of inter-turn insulation of voltage and current transformers.
5. Specialized testing equipment for new energy and foreign trade sectors
DEMIKS POWER has launched a customized testing machine on its official website, compatible with photovoltaic step-up transformers, American-style box-type substations, and high-voltage testing of rail transit traction equipment. The equipment supports ANSI North American standard testing procedures and bilingual reports, providing compliant testing hardware support for complete electrical equipment companies to expand into overseas markets.
IV. Industry Value of this Cooperation and Subsequent Technical Service Plan
The introduction of the DEMIKS POWER partial discharge withstand voltage-free partial discharge system by Shandong Langyun Electric is a typical example of standardized quality inspection upgrades for domestic medium and high voltage complete set manufacturers. Currently, the domestic market for 10kV gas-insulated switch-gear and ring main units is facing increasingly stringent regulations. Power grid bidding and third-party type testing both mandate that manufacturers have their own partial discharge withstand voltage testing stations. Low partial discharge and digital integrated testing equipment have become the core hardware support for enterprises’ competitiveness.
Based on the long-term strategic cooperation framework, Shanghai DEMIKS POWER will continue to provide Shandong Langyun Electric with three major supporting services: first, lifetime equipment calibration and annual on-site maintenance; second, insulation testing technical support during the new product development stage, providing a special partial discharge testing optimization solution for environmentally friendly fluorine-free gas-filled switch-gear; and third, software upgrades for equipment supporting the company’s foreign trade orders, adapting to the testing standards and report format requirements of overseas customers.
In the future, DEMIKS POWER will continue to leverage its online product showcase and technical solution consultation channels on its official website www.demikspower.com to provide high-performance, standardized high-voltage testing solutions to high and low voltage switch-gear manufacturers, transformer manufacturers, and power maintenance units nationwide. By providing professional high-voltage testing equipment, DEMIKS POWER aims to empower the high-quality development of the power distribution equipment manufacturing industry and enhance the export competitiveness of domestic high-voltage electrical products in both domestic and international markets.
Related DEMIKS product links: Partial Discharge-Free Power Frequency Withstand Voltage Test Device, Partial Discharge Comprehensive Detector, Gas-Fired Partial Discharge-Free Test Transformer, 10kV SF6 Gas-Fired Switch-gear Partial Discharge Withstand Voltage Test, Ring Main Unit Factory High Voltage Test Equipment, DEMIKS POWER High Voltage Test Equipment, Switch-gear Insulation Performance Test Equipment, Variable Frequency Series Resonant Withstand Voltage Device, High Voltage Complete Set Plant Quality Inspection Equipment Solution, Partial Discharge-Free Partial Discharge Withstand Voltage Integrated Machine, Power Equipment Type Testing Instruments , Gas-Fired Switch-gear Partial Discharge Detection System.
