Impact of Grounding Resistance on Zero-Sequence Voltage Rise in Different Grounding Systems

In an arc - suppression coil grounding system, the rising speed of the zero - sequence voltage is greatly affected by the value of the transition resistance at the grounding point. The larger the transition resistance at the grounding point, the slower the rising speed of the zero - sequence voltage.

In an ungrounded system, the transition resistance at the grounding point has basically no impact on the rising speed of the zero - sequence voltage.

Simulation Analysis: Arc - suppression Coil Grounding System

In the arc - suppression coil grounding system model, the influence on the rising speed of the zero - sequence voltage is analyzed by changing the value of the grounding resistance. From the zero - sequence voltage waveform in the figure, it can be seen that when the grounding resistances are 500 Ω, 1500 Ω, and 3000 Ω, the larger the resistance, the slower the rising speed of the zero - sequence voltage.

Fault initiation: The rising speed of the zero - sequence voltage makes the change of the sudden change amount not obvious. When using the sudden change amount of the zero - sequence voltage for initiation, the issue of parameter setting should be considered.

Fault diagnosis: When the criteria of the method adopted in fault diagnosis use the zero - sequence voltage data, the influence of the rising speed of the zero - sequence voltage on the diagnosis should be considered.

Simulation Analysis: Ungrounded System

In the ungrounded system model, as can be seen from the zero-sequence voltage waveform in the figure, when the grounding resistances are 500 Ω, 1500 Ω, and 3000 Ω, the rising speed of the zero-sequence voltage shows no significant change with the increase of the resistance.

When a single-phase grounding fault occurs, some fault characteristic quantities differ significantly between the arc-suppression coil grounding system and the ungrounded system. Therefore, during fault diagnosis, it is necessary to distinguish and consider them separately, and analyze and solve problems in a specific manner based on the actual situation.