Method and device for detecting line optical difference protection ratio brake curve

Abstract

The invention relates to the field of power system relay protection and discloses a method and a device for detecting a line optical difference protection ratio brake curve. The method specifically includes: putting two optical difference protection devices at a same place, connecting the same through optical fiber, setting starting current, knee point current and slope of the optical difference protection devices, starting a six-phase differential function of a relay protection tester to output three-phase current to the optical difference protection devices respectively, and using a ratio brake curve automatic drawing function of the relay protection tester for detection. The device overcomes distance and instrument limitation, does not need multiple-person cooperation and is simple andconvenient to operate, accurate in detection result and free of optical fiber channel and outside interference. The method and the device realize ratio brake characteristic detection to enable opticaldifference protection experiments to be more complete, avoid optical difference protection maloperation and ensure safe and stable running of a power grid.

Description

technical field [0001] The invention relates to the field of relay protection of electric power systems, in particular to a method for detecting the ratio braking curve of a line light difference protection device, and a device for detecting the ratio braking curve of a line light difference protection device. Background technique [0002] Due to the collection of electrical quantities on both sides of the line, the optical fiber differential protection has a fast action speed, high sensitivity, and is not affected by changes in the operating mode. As the main protection of the line, it is more and more widely used in the power grid. like figure 1 It is the schematic diagram of light difference protection. In order to improve the selectivity and sensitivity of protection, the line light difference protection device adopts ratio braking differential protection. It is of great significance to test its ratio braking characteristics. However, since the two optical difference pr...

AI Technical Summary

Problems solved by technology

Although the "off-site joint debugging method" can detect channel performance, simulate line faults during empty charging or no-load, simulate weak feed function and remote tripping function, it has major defects: it cannot detect the most basic ratio braking characteristic of differential protection, The reasons are as follows:

[0004] 2. The output current phase of the two places is difficult to be consistent

Even if two relay protection testers of the same model are used, due to the different initial phase angles, the output current phases will be different, resulting in the inability to match the currents on both sides.

[0005] 3. The cooperation between the test personnel in the two places is complicated

Two groups of testers are required to use two relay protection testers to cooperate with each other, and the operation is difficult

[0006] 4. The test result is not accurate

Due to the connection through several kilometers of optical fiber channels, the information interaction between the two optical difference protection devices is bound to be affected by channel attenuation, bit errors, out-of-step and external electromagnetic interference, and it is impossible to accurately interconnect the currents collected at both ends. , so it is difficult to accurately detect the ratio brake curve

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