# Performance Optimization of Grounding System for Multi-Voltage Electrical Installation
## 5 Comparative Analysis of Grounding Performance
### 10 kV System (Medium-Voltage) Grounding  
Soil variations significantly affect ground potential rise (GPR) in 10 kV grounding systems is primarily governed by factors such as soil resistivity, moisture content, temperature, and composition. High soil resistivity, typically observed in arid or sandy soils, results in increased GPR due to limited current dissipation, potentially causing hazardous voltage gradients [22]. Conversely, low resistivity in moist or clay-rich soils enhances current flow, reducing GPR. Temperature variations impact resistivity, with higher temperatures generally increasing resistivity and raising GPR, while lower temperatures reduce resistivity and lower GPR. Furthermore, soil layer stratification with differing resistivities can cause uneven current distribution, further affecting GPR. The 10 kV flexible grounding device topology is shown in Figure 5. \(E_{A}\), \(E_{B}\), and \(E_{C}\) are the three-phase voltages, while \(R_{x}\) and \(C_{x}\) (\(x=A,B,C\)) represent the network's equivalent resistance and capacitance. \(T\) is the step-up transformer, and \(R_{0}\) is the neutral grounding resistance. The device injects compensation current \(I_{i}\) at the neutral point, with \(L_{0}\) and \(C_{0}\) serving as the filter inductance and capacitance. In a phase \(C\) ground fault, \(R_{f}\) represents the transition resistance. Table 8 shows the impact of flexible grounding on fault current reduction. Upon a grounding fault, the flexible grounding device effectively suppresses fault current to zero and fully compensates residual current, achieving 100% transient arc extinguishment. Compared to ungrounded and small-resistance grounding modes, integrating a flexible grounding device with small-resistance grounding provides superior residual current suppression and higher arc extinction reliability. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Configuration** & **Description** & **Cost-Effective Solutions** \\ \hline Solid Grounding & Neutral point directly connected to the ground, providing a low-impedance path. & Simple, low-cost solution; suitable for smaller systems where fault currents are manageable. \\ \hline Resistance Grounding & A resistor is used between neutral and ground to limit fault current. & Low-cost resistors can be used; reduces fault current and minimizes the risk of equipment damage. \\ \hline TN-S System & Separate neutral and ground conductors, neutral directly grounded at the source. & Common in residential/commercial installations; cost-effective, especially for lower-risk fault scenarios. \\ \hline TN-C-S System & Combined neutral and ground conductor used for part of the system and separate for the rest. & Economical for residential and commercial installations, as it reduces the need for multiple conductors. \\ \hline Multiple Grounding Electrodes & Use of multiple ground rods or plates to increase surface area for fault current dissipation. & Cost-effective for larger systems; uses affordable electrodes to reduce resistance and improve fault current flow. \\ \hline Equipotential Bonding & Bonding all metallic parts (e.g., pipes, structures) to the grounding system. & Inexpensive and ensures that all conductive parts are at the same potential, reducing shock hazards. \\ \hline Earthing Conductors & Use of low-resistance, copper or aluminum conductors for connecting to the ground. & Use aluminum conductors instead of copper for cost savings while maintaining safety and efficiency. \\ \hline Use of Grounding Plates & Grounding plates (e.g., copper or galvanized steel) buried in the ground. & A cost-effective solution in areas with high soil resistivity; provides good fault current dissipation. \\ \hline Soil Conditioning & Chemical additives or conductive backfill materials to improve soil conductivity. & Inexpensive chemical treatments or backfill solutions can lower soil resistivity, improving grounding performance. \\ \hline \hline \end{tabular}
\end{table}