At present, the DC feed network of the substation mostly adopts a tree structure. From the storage battery to the electrical equipment in the station, it generally passes through three levels of power distribution, and each level of power distribution mostly uses a DC circuit breaker as a protective electrical appliance. Due to the mismatch of the protective action characteristics of the upper and lower DC circuit breakers, during the operation of the DC system, when a short-circuit fault occurs in the lower-level electrical equipment, it often causes the upper-level DC circuit breaker to skip tripping, thereby causing other feeder lines to cut off the power. Accidents, which in turn cause accidents in substation primary equipment such as high-voltage switches, transformers, and capacitors. In order to prevent hidden dangers caused by the mismatch of the action characteristics of DC circuit breakers and other DC protection appliances, the State Grid Corporation of China stipulates that the ampere-second characteristic test must be carried out for newly installed and operating DC protection appliances to ensure that the performance is consistent with the design to ensure The correctness of the DC link level difference coordination. Article 12, paragraph 8 of the "DC Power Supply System Operation Specification" issued in 2005 stipulates that "DC fuses and air circuit breakers shall be of qualified quality products, and their fuse links or fixed values shall be configured and set in accordance with relevant regulations. Check regularly to prevent accidents from expanding due to incorrect actions"; Article 27 of the "Technical Supervision Regulations on DC Power Supply System" stipulates: "...the automatic air circuit breaker should be checked for characteristics and operating current before use...."; Article 11 of "Measures to Prevent Accidents in DC Power Supply System" stipulates: "...should conduct ampere-second characteristic and operating current sampling before use...".
The ampere-second characteristics of DC protection appliances are generally tested in national-level laboratories or testing stations. The equipment covers a large area and needs to be equipped with special charging devices and high-current load boxes. The operation is complicated; some operating units use substation battery packs to protect DC The level difference of the electrical appliance is matched with the test, but the current-action time characteristic cannot be accurately tested. As a result, after the DC system is put into operation, the on-site maintenance personnel cannot check whether the ampere-second characteristics of the DC protection device meet the requirements because they do not have the corresponding testing methods and tools.
According to the actual conditions of the ampere-second characteristic test of DC protection appliances, our company has introduced a comprehensive system for the ampere-second characteristic test and level difference coordination of DC circuit breakers that is suitable for field use in substations, is easy to carry, and has a high degree of automation. It can provide DC for operation and maintenance departments. The testing method for the action characteristics of the protection electrical appliances is to verify the action characteristics and the level difference coordination of the DC protection appliances, so as to improve the reliability of the DC system operation and ensure the safe and reliable operation of the power grid.
Power input: 220V±10%, frequency: 50Hz±0.5 Hz;
Test current range: 0-500A;
Test voltage range: 0-1.0V;
Test current ripple coefficient: less than 5%;
Stability of output current: ≤0.5%;
Time record: 0-9999S; minimum time resolution: 0.1mS;
Ambient temperature: -20°C to 50°C
Dimensions: 470mm (length) × 320mm (width) × 460mm (height);
Weight: 20kg
The instrument can be used alone or online with a PC.
The instrument provides a large DC current source, which is easy to use and does not need to provide a DC power source such as a battery.
320×240 liquid crystal display, high-speed thermal printer, man-machine dialogue and full keyboard operation mode, intelligent work in the whole process.
Adopting power electronic control technology to produce DC high current output, the output current has fast response speed, high precision and continuously adjustable.
Multiple high-precision sensors automatically switch the current range and high-performance 14-bit AD acquisition chip.
With power-down storage function, 1000 sets of test data can be stored.
The setting data is automatically saved, and the last setting data is displayed after the power is turned on.
There are five major tests: ampere-second action test, flow-through non-action test, trip test test, differential coordination test, and internal resistance test test. Fully compatible with full-point test and sampling test.
The instrument provides RS232 communication interface, and the computer can control the instrument and export test data.
In the online mode, you can operate and control the instrument, import test data, store test data, generate data reports, generate data curves, generate EXCEL reports, etc.
The instrument has overheating, overcurrent, and overvoltage protection functions.
The instrument has strong anti-interference ability and strong electromagnetic compatibility.
Mobile version
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