Performance Evaluation of Solid-State Grounding

The solid-state grounding has been introduced as a new design of grounding systems for power system equipment that produces harmonic distortion. This new grounding system is constructed from a 3ϕ current-source, ac-dc power electronic converter, the output of which is connected to a grounding impedance (ZG). The frequency characteristics of ZG can be selected to meet standardized and recommended features of different grounding systems. This paper presents a performance evaluation of the solid-state grounding system, when used for various power system equipment, including those capable of producing harmonic distortion. Performance evaluation is conducted using laboratory synchronous generator and grid-connected battery storage system. Experimental tests are conducted for low-resistance and high-resistance solid-state grounding systems. The performance of the solid-state grounding systems is evaluated in terms of ground potentials, ground currents, and harmonic distortion factors. Test results show encouraging abilities of solid-state grounding systems to limit ground potentials and currents, while minimizing the harmonic distortion. Performance features of solid-state grounding systems are further demonstrated through comparisons with other grounding systems under similar operating conditions.