Power System Automatic Reclosing
Introduction
Power system automatic reclosing is a vital component in the efficient and reliable operation of modern electrical transmission and distribution systems. Automatic reclosing of power lines allows for quick clearing of fault locations, and greatly reduces the amount of time customers are without power due to line faults.
History
The idea of automatic reclosing originated in the early 1900’s with manual pilot relays. Described as rudimentary by modern standards, these relay systems were set up to operate in a pre-programmed sequence of events after detecting a line fault. While not completely automatic, these pilot relay systems did allow power lines to be cleared and reenergized quickly and reliably.
The first truly automatic reclosing system was developed in the 1950’s. This system used new solid state components and a digital controller to control the reclosing process. This allowed for a more sophisticated system with greater reliability, better communications, and improved safety features.
In the 1970’s, microprocessor controls replaced the digital controllers of the previous automatic reclosing systems. Microprocessors allowed for more precise and precise timing of the trip and restart sequence, as well as enhanced safety features.
Today’s modern automatic reclosing systems use a combination of microprocessors and digital controls to provide reliable and precise operation.
Operation
The basic principle of an automatic reclosing system is that its operation is initiated when a power system disturbance is detected. This disturbance can be a line fault, an overcurrent, a voltage dip or other power system disturbance.
Once the system determines a disturbance has occurred, the reclosing sequence is initiated. The system monitors the time and current of the power system, and uses this data to make decisions on when to trip and when to restart the line.
The system is programmed with certain rules on when to trip and when to reclose a line. Once these thresholds are met, the system automatically trips the line and clears the fault location, and then recloses the line and restores power to customers as quickly as possible.
Safety/Integration
Safety is of utmost importance in any power system, particularly when it comes to automatic reclosing. Automatic reclosing systems typically include multiple safety features and safeguards to ensure the safety of personnel and equipment.
These safety features typically include the use of sensors to detect overcurrents and arc flashes, as well as electrical isolation devices to ensure the system does not send power to the wrong location.
In addition to safety features, automatic reclosing systems are typically integrated with other power system components. For example, a reclosing system may be linked with a line protection system to provide additional safety and protection.
Conclusion
Automatic reclosing is an essential component in the efficient and reliable operation of modern electrical transmission and distribution systems. With the use of modern microprocessor and digital controls, these systems are capable of providing quick, reliable, and precise service to customers after a power system disturbance. Furthermore, with the use of safety features and integration with other power system components, automatic reclosing systems provide an essential service with minimal risk.
