DC Circuit Breaker Ampere Second Characteristics Testing System

Product Overview

The DC short-circuit device ampere second characteristic testing system is a commonly used protective component in DC systems of power system substations and power plants. Its good performance and practicality have been unanimously recognized and widely applied. At present, the DC power supply network mostly adopts a tree structure, from the battery to various electrical equipment in the station, generally passing through at least three levels of distribution. With the increasing demand for DC power supply in power plants and substations to control loads and power loads, the requirements for overload protection and short circuit protection of their protective electrical appliances are also becoming more and more strict. They cannot have any refusal or misoperation, especially over level misoperation, which will cause damage to power equipment and system failures, and even lead to large-scale power outages. The occurrence of over class misoperation is mainly due to unreasonable selection of protective electrical appliances and unstable performance of circuit breakers. Due to the inappropriate short-circuit characteristics of DC circuit breakers, during the operation of DC systems, when short-circuit faults occur in the underlying electrical equipment, it often causes the tripping of the higher-level DC circuit breaker, which is also known as leapfrog tripping. This leads to power outages in other feeder lines, further expanding the fault and seriously endangering the safe operation of the power grid. In order to prevent such over class tripping accidents, it is necessary to test the ampere second characteristics of various small DC circuit breakers in the DC system, determine the tripping time of circuit breakers under different short-circuit currents, effectively analyze the ampere second characteristics and protection level coordination of small DC circuit breakers, and verify whether the level difference coordination between upper and lower circuit breakers in the DC system is reasonable.

However, the technical specifications of small DC circuit breakers currently used in the power system are provided by manufacturers at the time of equipment delivery. On site maintenance personnel are unable to confirm whether the safety characteristics of small DC circuit breakers meet the requirements due to the lack of corresponding testing methods. Moreover, operational practice has proven that over time, the safety characteristics of the equipment will also change, especially after 3 years of operation, if the technical indicators of the equipment deviate, the typical consequence is a change in the characteristics of the circuit breaker, resulting in refusal or misoperation.

At present, the institutions and manufacturers in China that conduct small-scale DC circuit breaker ampere second characteristic testing use fixed equipment for DC circuit breaker ampere second characteristic testing, such as fixed high current power supplies and large load resistors, which are large in size and weight, and are not convenient for mobile testing. Analytical instruments are conventional instruments such as voltmeters, ammeters, oscilloscopes, etc., with complex wiring and inconvenient use, and are not suitable for mobile testing needs in various substations. To solve the problem of detecting the actual characteristics of small DC circuit breakers on site, we have independently developed a set of DC circuit breaker ampere second characteristic testing system suitable for mobile use in power systems.

This instrument is launched based on long-term on-site operation experience and multiple advanced technologies at home and abroad. It can achieve the detection and testing of the ampere second characteristics of small DC air switches with different capacities, providing a constant high current of 1-1000A, and can output larger currents through expansion. can

Test the tripping time of the circuit breaker under different short-circuit currents to verify whether the ampere second characteristics of the circuit breaker meet the requirements. This instrument adopts a new high-speed microprocessor and is equipped with a large screen LCD display. On site operation has shown that the instrument has excellent functionality, high reliability, simple structure, and easy operation.

GDAS-1000 DC Circuit Breaker Ampere Second Characteristics Testing System

Features

characteristic

• It can be tested online under PC control or offline, and the testing points can be flexibly programmed;
• The current range can be as small as 1A, with precise control and testing within the range of 1-1000A. The constant current accuracy is high, the load capacity is strong, and it can work stably for a long time;
• The host adopts a 32-bit new high-speed ARM processor combined with a large-scale CPLD, which is fast, reliable, and has excellent performance.
• This machine adopts a 320 × 240 dot matrix large screen high-resolution graphic LCD display, and all operations are completed through the keyboard. The testing process is set on the display screen, and the operation interface and test results are displayed in Chinese, making the operation intuitive and clear.
• Circuit breaker cascade testing can be performed.
• This machine can store up to 1000 test data, which can be queried at any time, uploaded to a computer, and uploaded to a USB drive.
• Randomly equipped with a PC testing management program, which can control the testing process. All test data can be
• Storage and printing, generating reports directly.

  function

  According to the GB10963-1999 standard for overcurrent protection circuit breakers used in household and similar places, circuit breakers should undergo a trip characteristic test.

• Time current characteristic test

  Starting from the cold state, apply a current of 1.13In (agreed non trip current) to the circuit breaker until the agreed time, and the circuit breaker should not trip. Then, within 5 seconds, stabilize the current to a current of 1.45 In (specified tripping current), and the circuit breaker should trip within the specified time.

  Starting from the cold state, a current of 2.55In should be applied to each stage of the circuit breaker, and the disconnection time should be greater than 1s. For circuit breakers with a rated current of 63A or less, the disconnection time should be less than 60s, and for circuit breakers with a rated current greater than 63A, the disconnection time should be less than 120s.

• Instantaneous release test

  For B-type circuit breakers: starting from the cold state, apply a current of 3In to each stage of the circuit breaker, and the disconnection time should be greater than 0.1s; then starting from the cold state, apply a current of 5In to each stage of the circuit breaker, and the disconnection time should be less than 0.1s.

  For C-type circuit breakers: starting from the cold state, apply a current of 5In to each stage of the circuit breaker, and the disconnection time should be greater than 0.1s; then starting from the cold state, apply a current of 10In to each stage of the circuit breaker, and the disconnection time should be less than 0.1s.

  For D-type circuit breakers: starting from the cold state, apply a current of 10In to each stage of the circuit breaker, and the disconnection time should be greater than 0.1s; then starting from the cold state, apply a current of 50In to each stage of the circuit breaker, and the disconnection time should be less than 0.1s. Both tests should meet the time current action characteristic table.

  experiment	type	Test current	initial state	Limit when tripped or not tripped	expected result
  a	B 、 C ， D	1.13In	cold state	t≧1h(In≦63A) t≧2h(In>63A)	Do not release
  b	B 、 C 、 D	1.45In	Immediately following Experiment A	t<1h(In≦63A) t<2h(In>63A	trip
  c	B 、 C 、 D	2.55In	cold state	t<1h(In≦63A) t<2h(In>63A)	Do not release
  d	B 、 C 、 D	3In,5In 10In	cold state	1s 1s	trip
  e	B 、 C 、 D	5In 10In50In	cold state	t<0.1s

Main technical parameters

• High output current: 1000A, expandable to 2000A.
• Output current accuracy: ± 1%.
• Current adjustment range: 1-1000A, expandable to 1-2000A.
• Current output response time: 4ms.
• Time measurement accuracy: 1% ± 5ms.
• Working power supply: 220V ± 15%.
• Weight: 50KG.