Transient Ground Fault Function

Sensitive, digital transient ground fault function. Detection of fault location in the grid. Enhances availability. Conserves Equipment.

Low-impedance ground faults are generally managed reliably with protection devices like the SIPROTEC 7SN60. The high sampling rate of SIPROTEC 5 devices allows for the integration of new, sensitive digital procedures for the reliable detection of high-impedance ground faults. The parts of the signal which are caused by the discharging and charging of the ground capacitances of the grid are of particular interest here. The active power in the zero-sequence system is a good criterion to detect the direction of the ground fault. As the charging takes place over a longer period of time with high-impedance ground faults, this part of the active power is available during this time period and can be integrated right from the ignition of the fault. This results in the active energy in the zero-sequence system.

Radial systems do not pose a problem for determining the direction. In meshed systems, operational zero-sequence currents can falsify the resulting direction. These operational zero-sequence currents are eliminated by the new algorithm in order to determine the correct direction.

Benefits of the innovative transient ground fault function

  • Cost savings thanks to integration in SIPROTEC 5

  • Very high sensitivity - detection of high-impedance faults with fault resistances of up to 5 kohms

  • Detection of very short ground faults of few milliseconds

  • Ideally suited for closed loops or meshed systems, as not impacted by operational zero-sequence currents

  • Easy setup of the function