Evaluation of the Distance of the BondedInstrumentation and HV GS to Reduce theElectromagnetic Interferences due to LightningStrikes

The characteristics and structure of HighVoltage (HV) and Low Voltage (LV, instrumentation, or cleanearth) Grounding Systems (GS) are different. So they shouldbe placed at an optimal distance so that if the lightning currentis rejected from the HV GS to the clean earth, its waves willnot affect the instrumentation ground. The conduction of thelightning current wave and the fault current to the ground isassociated with an increase in the voltage of the conductivepart of the connection of this system to the local groundreference. Therefore, GSs are inherently prone to noise.Reducing the incidence of noise interference in instrumentationsystems by creating joint surfaces with low relative impedancebetween devices, circuits, and equipment is one of the maingoals of GSs. The voltage wave in the buried electrodes of theGS creates potential levels that are eventually dumped. Theimpact of lightning current in the substation environmentthrough the path of closed current loops can cause themisperformance of sensitive equipment. In this paper, withsuitable modeling of low voltage and sensitive electronicequipment, the effect of lightning current on the lightningprotection GS, the amount of injected current and, voltageInduction to GSs of bonded instrumentation and HV GS isinvestigated. The parameters affecting the induced voltage,such as the shape of the electrodes, and the soil resistivity arealso investigated. All the simulations of this paper have beendone in the EMTP-RV environment.

کلیدواژه ها:

Grounding system ، Instrumentation ، Lightningwave ، overvoltage