What are the best practices and tools for transient protection and mitigation?

1 Transient sources and types

The main sources of transients in power systems are switching operations, such as circuit breakers, disconnectors, transformers, and capacitors, that create arcs, sparks, or oscillations. Other sources include faults, such as short circuits, ground faults, or open circuits, that create voltage surges or dips. Lightning strikes are another common source of transients, especially for overhead lines, that generate high-frequency impulses. Depending on the frequency, duration, and magnitude of the transients, they can be classified into three types: impulse, oscillatory, and temporary.

2 Transient effects and risks

Transients can have a wide range of effects and risks on power systems, depending on their characteristics and the vulnerability of the components. For instance, overvoltage and overcurrent can lead to breakdown, flashover, or overheating, which can cause equipment failure, fire, or explosion. Additionally, transients may introduce harmonics and resonance that distort the waveform, reduce the power factor, and interfere with protection and control devices. This can affect the power quality and reliability of the system. Furthermore, transients may emit electromagnetic waves that cause noise or errors in data and control systems.

3 Transient protection and mitigation

The main objectives of transient protection and mitigation are to prevent or limit the occurrence and propagation of transients, as well as reduce or eliminate their harmful effects. To do so, there are several best practices and tools that can be employed, such as grounding and bonding to provide a low-impedance path for the dissipation of transient currents and voltages, surge arresters to divert or suppress transient surges, snubbers and filters to attenuate or eliminate oscillations, and switching techniques and devices to control or minimize the generation and propagation of transients. All of these methods help to reduce the risk of electric shock, electromagnetic interference, resonance, harmonics, and more.

4 Transient analysis and simulation

Transient analysis and simulation are techniques and tools that help power engineers to understand, predict, and evaluate the behavior and impact of transients in the power system. These involve the use of mathematical models, software programs, and hardware devices that represent the physical and electrical characteristics of the system and the transient sources. Through these tools, engineers can identify and quantify transient sources and types, assess the associated risks on system components, design and optimize protection and mitigation measures, as well as test and verify the performance of these devices.

5 Transient measurement and monitoring

Transient measurement and monitoring are techniques and tools that enable power engineers to detect, record, and analyze the transients that occur in the power system. This is done through the use of sensors, meters, oscilloscopes, and data loggers that measure and display the transient waveforms, parameters, and events. Utilizing these tools, power engineers can validate and calibrate transient analysis and simulation models, diagnose and troubleshoot transient problems and faults, evaluate and improve the effectiveness of transient protection and mitigation devices, as well as maintain and update said devices.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?