An electronic apparatus is provided. The electronic apparatus includes: a main circuit; and a power supply circuit configured to receive external power from an external power supply and supply operating power to the main circuit. The power supply circuit includes: a converter; and a lightning protection circuit that includes: a varistor configured to have a first rated voltage corresponding to a breakdown voltage of a device of the converter; and a surge arrester connected in series to the varistor and configured to have a second rated voltage, and based on the external power being higher than the first rated voltage of the varistor, the varistor is clamped so that a voltage applied to the converter does not exceed the first rated voltage, and based on a voltage applied to the surge arrester being equal to or higher than the second rated voltage, the surge arrester is short-circuited.

An electronic apparatus is provided. The electronic apparatus includes: a main circuit; and a power supply circuit configured to receive external power from an external power supply and supply operating power to the main circuit. The power supply circuit includes: a converter; and a lightning protection circuit that includes: a varistor configured to have a first rated voltage corresponding to a breakdown voltage of a device of the converter; and a surge arrester connected in series to the varistor and configured to have a second rated voltage, and based on the external power being higher than the first rated voltage of the varistor, the varistor is clamped so that a voltage applied to the converter does not exceed the first rated voltage, and based on a voltage applied to the surge arrester being equal to or higher than the second rated voltage, the surge arrester is short-circuited.

The invention relates to an improved surge protection device comprising a fast acting, self-restoring circuit breaker, preferably, along with surge arrestor/absorber to improve the protection and availability of the equipment which is in use with power source affected with surges/spikes which otherwise would have operated the spike/surge arrestor in-built in the equipment that would have led to its non-availability, and protection for equipment that may or may not be having in-built overcurrent, surge protection devices.

The invention relates to an improved surge protection device comprising a fast acting, self-restoring circuit breaker, preferably, along with surge arrestor/absorber to improve the protection and availability of the equipment which is in use with power source affected with surges/spikes which otherwise would have operated the spike/surge arrestor in-built in the equipment that would have led to its non-availability, and protection for equipment that may or may not be having in-built overcurrent, surge protection devices.

A detection scheme for temporary overvoltages and/or ground fault overvoltages in electric power systems is described. Current passing through a surge arrestor component of the power system is monitored. An algorithm for identifying one or more frequency components of the measured current signal is performed to screen out unwanted harmonics. In some embodiments, this is a frequency domain analysis. The frequency component(s) of the current signal is then compared to a calculated pickup current or pickup voltage of the system to determine if system protection steps should be undertaken.

A detection scheme for temporary overvoltages and/or ground fault overvoltages in electric power systems is described. Current passing through a surge arrestor component of the power system is monitored. An algorithm for identifying one or more frequency components of the measured current signal is performed to screen out unwanted harmonics. In some embodiments, this is a frequency domain analysis. The frequency component(s) of the current signal is then compared to a calculated pickup current or pickup voltage of the system to determine if system protection steps should be undertaken.

A system and method for suppressing EMP-induced electrical system voltage surges due to detonation of a nuclear weapon, the EMP comprising E1, E2, and E3 component pulses. A plurality of shunting assemblies, each including MOVs, gas discharge tubes, other mechanical, electrical and ionization discharge devices and combinations thereof, detect and react to the overvoltage according to timing parameters associated with each of the E1, E2, and E3 components and shunt the overvoltage to decrease to under a predetermined allowable level. Respective shunting assemblies may include automatic self-monitoring of any faults in respective circuitry and also a challenge mode for on-demand circuit monitoring using an optical coupling switch, the optocoupler including an infrared light supplied by an LED flashlight and having a phototransistor light receiver.

Provided are a load transfer method and system in thunder and lightning weather. The method includes: detecting lightning and predicting a position and time of a lightning strike to obtain a lightning prediction result; determining a transmission line possibly struck by lightning in a power grid according to the lightning prediction result; determining a load transfer scheme; and before the lightning occurs, transferring at least part of loads on the transmission line possibly struck by lightning according to the load transfer scheme.

An overvoltage protection circuit includes an input terminal, an output terminal, a clamp transistor, and a selector circuit. The clamp transistor is configured to control current flow between the input terminal and the output terminal. The clamp transistor includes a first terminal coupled to the input terminal, a second terminal coupled to the output terminal. The selector circuit is configured to control a resistance of the clamp transistor based on a voltage at the input terminal. The selector circuit includes a first terminal coupled to the first terminal of the clamp transistor, a second terminal coupled to the second terminal of the clamp transistor, and a third terminal coupled to a third terminal of the clamp transistor.

A switch gear system is described. In some implementations, a switch gear arrestor system can include a switch gear and one or more arrestors mounted on a non-conductive insulated bar. The one or more arrestors can be connected to one or more isolators through a respective aperture in the non-conductive insulated bar. Each arrestor can be connected to one of the one or more electrical energy sources at a first end and can be connected to one of the one or more isolators at a second end. The switch gear arrestor system can further include one or more ground leads. Each ground lead can connect one of the one or more isolators to a conductive grounding bar.