HZDK-1000 1000A DC Switch Ampere-Second Characteristic Tester

I. Overview

At present, the DC feeder network of the substation mostly adopts a tree structure. From the battery to the power equipment in the station, it generally goes through three levels of power distribution, and each level of power distribution mostly uses DC circuit breakers as protective devices. Due to the mismatch of the protection action characteristics of the upper and lower DC circuit breakers, when a short circuit occurs in the lower power equipment during the operation of the DC system, it often causes the DC circuit breaker of the upper level to trip, thereby causing power outages in other feeder lines, and then causing accidents in the primary equipment of the substation such as high-voltage switches, transformers, capacitors, etc. In order to prevent the hidden dangers caused by the mismatch of the action characteristics of DC circuit breakers and other DC protective devices, the State Grid Corporation of China has stipulated that the ampere-second characteristic test must be carried out for newly installed and operating DC protective devices to ensure that the performance is consistent with the design, so as to ensure the correctness of the DC circuit differential coordination. Article 12, Paragraph 8 of the "DC Power System Operation Specifications" issued in 2005 stipulates that "DC fuses and air circuit breakers should be of qualified quality, and their fuses or settings should be graded and adjusted in accordance with relevant regulations, and checked regularly to prevent accidents from expanding due to incorrect operation"; Article 27 of the "DC Power System Technical Supervision Regulations" stipulates: "... automatic air circuit breakers should be subject to spot checks on characteristics and operating currents before use...."; Article 11 of the "Measures for Preventing Accidents in DC Power Systems" stipulates: "... spot checks on ampere-second characteristics and operating currents should be conducted before use..."

The ampere-second characteristics of DC protection devices are generally tested in national laboratories or testing stations. The equipment occupies a large area and requires a special charging device and a high-current load box, which is complicated to operate. Some operating units use substation battery packs to test the differential coordination of DC protection devices, but cannot accurately test their current-action time characteristics. As a result, after the DC system is put into operation, on-site maintenance personnel cannot verify whether the ampere-second characteristics of DC protection devices meet the requirements because they do not have the corresponding testing methods and tools.

According to the actual situation of the ampere-second characteristic test of DC protection devices, our company has launched a DC circuit breaker ampere-second characteristic test system that is suitable for on-site use in substations, easy to carry, and highly automated. It can provide the operation and maintenance department with a means of testing the action characteristics of DC protection devices, and calibrate the action characteristics and differential coordination of DC protection devices, so as to improve the reliability of DC system operation and ensure the safe and reliable operation of the power grid.

HZDK-1000 DC circuit breaker ampere-second characteristic test system is suitable for the ampere-second characteristic test of DC circuit breakers with a rated current of 1A to 1000A, and can be used for the ampere-second characteristic test of DC fuses with a rated current of 6A to 150A.

Technical Indicators

1. Power input: 220V±10%, frequency: 50Hz±0.5 Hz;

2. Test current range: 0-1000A;

3. Test current ripple coefficient: less than 5%;

4. Output current stability: ≤0.5%;

5. Time record: 0-999999S;

6. Ambient temperature: -20℃ to 50℃