surge suppressor Overview of IEEE Standard 242

by:KEBO      2019-10-21

IEEE 242 is one of the "color books" provided by IEEE.IEEE 242 is included in the color book "buff" or "yellow.
IEEE Standard 242 has been adopted by the National Standards Association (ANSI), which can be called ANSI/IEEE 242.
The IEEE 242 standard is regularly reviewed and maintained by the Buff Book Working Group, which is supervised by the power systems and protection board.IEEE 242 can be considered a power system protection manual outlining IEEE Recommended practices to protect the power system from damage in the event of a failure.
The electrical system protection and coordination described in IEEE standard 242 is designed to remove components from the power system after a short circuit of the power system or starting a fault.When an electrical fault occurs, the protection of the electrical system established through the power system should play the role of isolating the fault unit.If the recent fault protection is not working, additional backup protection should be triggered.

The reliability and protection levels of power systems vary.Reliability measures the possibility of failure.Protection measures measure the extent to which it continues to operate after a fault.High reliability systems may be poorly protected, resulting in a total failure after a surge in voltage.
A system with medium reliability may have a well-designed protection system with additional fuses, fault tolerances, Transformers and backup generators, so occasional failures do not affect the performance of the remaining systems.Setting high standards for reliability reduces the risk of serious equipment damage in the event of electrical failure.Improper replacement of the circuit breaker can cause sparks or short circuit, endangering people and equipment around.

IEEE 242 provides an overview of the short circuit capacity curve for Transformers.The short circuit capacity is determined according to the rated voltage and impedance.The current transformer provides secondary current proportional to the primary current.
IEEE 242 provides a method to evaluate the accuracy of current transformers in terms of distortion and proportion to primary current.Fuses can limit current or not, but they are used in both low and high voltage circuits.The current limiting fuse can only work within a specific current range.IEEE 242 provides calculations to determine which current limiting fuses should be used in the case of circuit design.
IEEE Standard 242 allows direct or per-unit basis.Per-Unit analysis is more suitable for systems operating at different voltage levels.Direct analysis of fault current using-Line chart, more suitable for power systems that operate only under one or two voltage levels.

The protection relay protects the power system in case of short circuit or overload.When abnormal conditions such as sudden spikes in voltage, the protection relay triggers the circuit breaker.Protective relays are usually used for applications running at 480 volts or more.
Fuses can be used for low voltage applications to provide protection.The type of electrical protection required for the system depends on the type of equipment used.IEEE 242 requires greater protection as the voltage rises.IEEE 242 discusses how ground fault protection coordination, also known as GFP coordination, can be achieved.
IEEE 242 licenseCurrent managed using pre-Programmable Solid State Relays.It also allows electricity.Mechanical pastCurrent relay to be used.IEEE 242 allows the system design to use a backup circuit to keep the system running when the main circuit fails.Standby circuit is activated when automatic throwingThe rail crossing is triggered by abnormal conditions such as low voltage, high voltage or too high or too low current.

IEEE 242 refers to other IEEE standards for components in power systems.The IEEE C37 series standard covers circuit breakers and switching equipment.The IEEE C57 series covers protection relays and Transformers.The IEEE C62 standard covers surge capacitors and surge inhibitors.
IEEE 62.2 An overview of the approval method for diagnostic testing of electrical equipment in machinery.IEEE 32-1972 describes the terms and test procedures used by ground equipment such as ground Transformers and ground faults neutralizer.
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