Explanation of the Earth Grid Design and its Purpose

The Earth grid system is a network of conductors, electrodes, and soil designed to provide a low-impedance path to the earth for electrical currents. Its purpose is to protect humans, equipment, and infrastructure from electrical hazards by providing a path of least resistance for fault currents to flow to the earth.

Earth grid design is important because it ensures the safety, reliability, and efficiency of electrical systems. A properly designed Earth grid helps to minimize the risk of electrical shocks, fires, and equipment damage. In addition, earth grid design also improves the performance of electrical systems by reducing energy loss and improving power quality.

Importance of Earth Grid Design

Earth grid design is essential for ensuring:

• Safety: Earth grid design plays a critical role in protecting humans and equipment from electrical hazards. Fault currents can occur due to lightning strikes, power surges, or equipment failures, and these currents can cause significant damage and even injury or death. A properly designed Earth grid, reducing the risk of electrical shock and preventing damage to electrical equipment.
• Reliability: Electrical systems must operate continuously without interruption. Earth grid design helps to ensure that electrical systems remain operational, even during fault conditions. The Earth grid helps to prevent equipment damage and reduce downtime.
• Efficiency: Earth grid design can also improve the efficiency of electrical systems by reducing energy loss and improving performance. Additionally, a well-designed grounding system can help reduce the risk of voltage fluctuations or surges that can cause equipment damage or downtime.

Problem Statement

To redesign an earth grid for a 765kV substation, as the cost of implementing the proposed earth grid design was exceeding the budget. As a renewable energy project, it created a unique challenge of grid stability and sub-synchronous resonance, at the point of coupling, compared to traditional energy transmission projects.

 Approach

The grid was re-designed and optimized using CDEG software and by enveloping the ground conductors with our OEM earth enhancement compounds Curec+® and Curecon® which perform as per IEEE 80 Clause 14.5 d & 14.5 b respectively.
At the time of fault or lightning, the current interaction capacity (A/m) of Curec+ and Curecon with earth grid conductor is approximately 6 and 1.5 times higher than electrical grade bentonite respectively. This enables to achieve low earth grid resistance and maintains grid potential within permissible limits along with a significant reduction in the buried length of grid conductors. Over and above, these products provide permanency to earthing systems.