High-Resistance Grounded Power System

Abstract

To minimize ground fault during a line-to-ground fault condition, it has been a common practice to use highresistance grounded (HRG) power systems, both at low voltage (LV) and at medium voltage (MV). The criteria for designing HRG systems are very well known to the industry; however, the opinions of industry experts have been divided on limiting the use of HRG systems for MV systems to voltages of less than 4.16 kV and phase-ground fault currents of less than 10 A without clarifying that it applies to systems which require continuous operation upon detecting first line-to-ground fault as it is now in reference [1]. This paper will review the background history of HRG power systems and their application to MV systems for specific industries and will make the case that voltages need not be limited to less than 4.16 kV and phase-ground fault current less than 10A, so long as the faulted power system is isolated within 10 cycles and there are no direct connected motors. This paper will discuss the potential damage and protection requirements of HRG systems for MV applications to ensure that a line-to-ground fault is cleared before it involves other phases to make a multiphase arcing ground fault.Index Terms-Arcing fault, fault resistance, ground fault protection relay, high-resistance grounded system, system charging current. 0093-9994 (c)

Assessing High-Voltage Shore Connection Safety: An In-Depth Study of Grounding Practices in Shore Power Systems

“…The HRG method effectively suppresses the fault current on the line, preventing overvoltage and ensuring the safety of personnel and equipment. The HRG method requires ensuring that the fault current is equal to or slightly higher than the system charging current [24,35,36]. In Section 6.2.3 of IEEE 80005-1, the fault current generated by the impedance should be at least 1.25 Two types of NGRs (R N ) are commonly used: HRG and LRG.…”

“…The HRG method effectively suppresses the fault current on the line, preventing overvoltage and ensuring the safety of personnel and equipment. The HRG method requires ensuring that the fault current is equal to or slightly higher than the system charging current [24,35,36]. In Section 6.2.3 of IEEE 80005-1, the fault current generated by the impedance should be at least 1.25 times the system charging current, with a value exceeding 25 A-5 s. However, the same shore power system paired with different ship types and electrical architectures can result in varying system charging currents [32].…”

“…The setting of the neutral grounding resistor (NGR) can help to reduce fault currents and ensure safety. Previous literature has discussed the selection of appropriate grounding resistance [24,[35][36][37].…”

“…System-Charging-Current Method [35,36] Figure 5 shows the fault current flow and phasor diagram of a U-phase-to-ground fault case of the NGR power system in HVSC. The dashed box represents the typical three-phase transformer configuration used in current shore power systems, following the IEC 60364 TN configuration.…”

Research on arc grounding identification method of distribution network based on waveform subsequence segmentation-clustering

“…The traditional arc-optic grounding fault identification method of the distribution network is based on the steadystate or transient electrical parameters and the set threshold (Chen et al, 2021), and in the fault identification method based on the transient electrical parameters, the characteristic parameters of the typical fault type are first extracted, including wavelet transform (WT) (Qin et al, 2018;Lin et al, 2019;Wei et al, 2020a), empirical mode decomposition (EMD) (Guo et al, 2019;Cai and Wai, 2022), and S transformation (ST) (Peng et al, 2019); Then, the arc ground fault is classified and identified by the pattern recognition method, mainly including the neural network method (Siegel et al, 2018;Du et al, 2019a), the Support Vector Machine (SVM) (Xia et al, 2019;Dang et al, 2022), the fuzzy control method (Zeng et al, 2016), the clustering (Wang et al, 2015), etc., in addition, the high-precision current transformer can be used to improve the fault identification ability (Paul, 2015), but the detection cost is also significantly increased.…”