Electrical transient overvoltage coordination, often referred to as "surge protection coordination," is a concept in electrical engineering that involves the careful selection and coordination of protective devices to safeguard electrical equipment and systems against transient overvoltages or voltage surges.
Transient overvoltages are short-duration voltage spikes or surges that can occur in power systems due to various factors, such as lightning strikes, switching operations, or faults. These voltage surges can cause damage to sensitive electronic equipment, appliances, and electrical systems if not adequately controlled and protected against.
The purpose of electrical transient overvoltage coordination is to ensure that the protective devices, such as surge protectors and overvoltage protection devices, are appropriately sized and positioned throughout the electrical system to provide effective protection against transient overvoltages. The coordination process involves the following key steps:
Risk Assessment: Identifying potential sources of transient overvoltages in the power system, such as lightning strikes or switching events. Understanding the equipment's sensitivity and vulnerability to overvoltages.
Surge Protective Device (SPD) Selection: Choosing the appropriate surge protective devices based on their voltage ratings, energy handling capabilities, and response times. Different types of SPDs are available for specific applications, including surge arresters, metal oxide varistors (MOVs), and gas discharge tubes.
Coordination Levels: Determining the coordination levels or zones in the electrical system where the SPDs will be installed. This involves strategically placing the protective devices to form a hierarchical protection scheme, with different levels of protection based on their response times and energy-handling capabilities.
Protection Coordination: Coordinating the time-current characteristics of the protective devices to ensure that the device closest to the equipment operates first during a transient overvoltage event. This prevents the surge from reaching sensitive equipment and allows the downstream protective devices to handle larger surges.
Grounding and Bonding: Ensuring proper grounding and bonding of the electrical system to minimize the effects of transient overvoltages and improve the effectiveness of surge protection.
Maintenance and Testing: Regularly inspecting, testing, and maintaining the surge protection devices to ensure their continued effectiveness and reliability.
By implementing effective electrical transient overvoltage coordination, electrical systems can minimize the risk of equipment damage, downtime, and data loss caused by transient overvoltages, making the entire system more robust and reliable. It is an essential aspect of electrical system design and plays a crucial role in protecting modern electronic devices and systems.