Product use

The device is suitable for the underground coal mine with explosive dangerous gas and coal dust, installed in the 10(6)kV underground central substation, substation in the mining area, using centralized synchronous real-time sampling, distributed control structure of high voltage selective leakage protection, suitable for the neutral point is not grounded or grounded by the arc suppression coil power supply system. It can quickly and accurately find the single-phase grounding fault line, and locate the fault within 20 meters, prevent the power system from leakage and tripping, and avoid large-scale power outage accidents. With optical fiber communication interface, it can access the power monitoring system through optical fiber to realize synchronous real-time remote monitoring.

Product overview

At present, the high voltage leakage protection in coal mine is partly realized by the leakage protection function in the high explosive switch. The line selection principle is based on the zero sequence power direction principle to realize the leakage protection of this branch. This method has simple algorithm and low judgment accuracy; In some mines, the high voltage system adopts the grounding method of the antiarc coil, which makes the zero sequence power direction principle in the failure state, resulting in the serious accident of leakage tripping phenomenon when the high voltage leakage occurs.

The selective leakage protection devices currently used in China have been proved by field use to have the defects of misoperation, unreliable operation and low accuracy of line selection. The main reasons are: (1) The sampling of the fault signal is not synchronous sampling, and the sampling of the fault signal is not the fault data at the time of the fault, but mostly the data sampling after the fault. (2) The principle is single, and the existing leakage protection device simply adopts the steady-state or transient method (commonly used principles: fifth harmonic method, injection signal method, pattern recognition method, grounding impedance method, etc.). It has been proved that these principles of line selection are too simple, and the correct rate of line selection is very low. It often causes misselection and missing selection, leading to major accidents of leakage tripping.

The results show that when leakage occurs in the high voltage system, the fault line selection based on the comprehensive criterion of attenuation DC component method, wavelet packet frequency division method, transient pulse characteristic method and first half wave method should be adopted according to the fault information of the whole power grid, so as to judge the correct fault point. Therefore, it is impossible to realize high-voltage leakage fault line selection only by relying on the collection information of a single branch, and it is easy to misjudge, refuse to move, and misjudge, even the whole bow | leakage tripping, resulting in greater power supply accidents.

This product really realizes the comprehensive fault line selection combining the steady state component and the transient component, establishes the fault event history database, and fills the technical gap in the field of selective leakage protection in China's coal mine high voltage power supply system.

Main feature

The shell adopts quick-opening, double-cavity structure design, modular installation, easy connection maintenance;

The control unit adopts FPGA+ dual-ARM embedded structural core processing technology, which has the characteristics of powerful function, fast processing speed and strong anti-interference ability.

Intelligent man-machine interface and fault information database query;

Adopt the latest digital processing technology and multiple advanced high-voltage leakage line selection principle;

At the same time, centralized monitoring of 4 busbars, 30 branches;

Especially for the design of coal mine power supply system grounded by arc suppression coil, the correct rate of line selection is more than 98%.

No need to modify the existing high-explosive switch;

The state of incoming and outgoing lines can be set to achieve upper and lower control, and the leakage anti-tripping network can be formed.

It can remember instantaneous grounding information, and can accurately distinguish between bus grounding and outlet grounding faults.

Main technical parameters

Product application topology diagram