Online monitoring system for grounding grid resistance

Abstract

The invention discloses an online monitoring system for grounding grid resistance, and relates to the technical field of power systems. The online monitoring system comprises a pilot power unit, a data acquisition unit, a filter analysis unit, a data processing unit, a system control unit, a communication unit and an external system, wherein the pilot power unit is connected with monitored power equipment, the monitored power equipment is connected with the data acquisition unit, the data acquisition unit is connected with the filter analysis unit, the filter analysis unit is connected with the data processing unit, and the system control unit is connected with the pilot power unit, the data acquisition unit, the filter analysis unit and the data processing unit respectively; and the system control unit is connected with the external system via the communication unit. The online monitoring system can timely monitor characteristic parameters of a grounding device, and timely monitor the grounding resistance indicator change trend of the grounding device, so that the relevant department can timely master the security of a grounding grid and formulate corresponding countermeasures, and personal and equipment safety accidents are effectively prevented.

Description

technical field [0001] The invention relates to the technical field of electric power systems, in particular to a measurement technology for grounding grid resistance, and in particular to an online monitoring system for grounding grid resistance. Background technique [0002] In recent years, many substations in China have caused expansion accidents due to lightning strikes, most of which are related to the unqualified grounding resistance of the grounding grid. The grounding grid plays the role of working grounding and protective grounding. The increase of the neutral point voltage offset may cause the sound phase and neutral point voltage to be too high, exceeding the level required by the insulation and causing equipment damage. [0003] When a lightning strike or lightning wave strikes, due to the large current, a high residual voltage will be generated, which will threaten the nearby equipment to counterattack, and reduce the protective equipment (overhead transmission...

AI Technical Summary

Problems solved by technology

[0002] In recent years, many substations in China have caused expansion accidents due to lightning strikes, most of which are related to the unqualified grounding resistance of the grounding grid. The grounding grid plays the role of working grounding and protective grounding. The neutral point voltage offset increases, which may make the sound phase and neutral point voltage too high, exceeding the level required by the insulation and causing equipment damage

[0003] When a lightning strike or lightning wave strikes, due to the large current, a high residual voltage will be generated, which will threaten the nearby equipment to counterattack, and reduce the protective equipment (overhead transmission lines and substation electrical equipment) of the grounding grid itself. Lightning resistance level, if it fails to meet the design requirements, the equipment will be damaged

At the same time, whether the grounding resistance of the grounding system is qualified is directly related to the personal safety of substation operators and substation maintenance personnel; but because the soil has a corrosive effect on the grounding device, as the operation time increases, the grounding device has been corroded, affecting the safety of the substation run

[0004] Therefore, it is necessary to vigorously strengthen the regular monitoring of the grounding resistance of the grounding grid; the measurement of the grounding resistance of the substation grounding grid in operation, due to the interference of the current flowing into the grounding grid from the system and the interference between the test lead wires, the test results have a large error

In particular, the grounding resistance of large-scale grounding grids is very small (generally below 0.5Ω), even slight interference will have a great impact on the test results; if the grounding resistance test of the grounding grid is not accurate, it will not only damage the equipment, but also cause such as Unnecessary losses such as grounding grid remodeling, so the grounding grid grounding impedance test and its test data have a non-negligible significance for the entire substation

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