Flexible AC transmission system (FACTS) enabling distributed controls is a requirement for power transmission and distribution, to improve line balancing and distribution efficiency. These FACTS devices are electronic circuits that vary in the type of services they provide. All FACTS devices have internal circuitry to handle fault currents. Most of these circuits are unique in design for each manufacturer, which make these FACTS devices non-modular, non-interchangeable, expensive and heavy. One of the most versatile FACTS device is the static synchronous series compensator (SSSC), which is used to inject impedance into the transmission lines to change the power flow characteristics. The addition of integrated fault current handling circuitry makes the SSSC and similar FACTS devices unwieldy, heavy, and not a viable solution for distributed control. What is disclosed are modifications to FACTS devices that move the fault current protection external to the FACTS device and make them modular and re-usable.

A method and apparatus for operating a power distribution system, includes providing a solid state switch downstream of a power source and upstream of an electrical load, the solid state switch operable in a conducting mode that enabling conduction from upstream to the output and a non-conducting mode that disables conduction from the input to the output, and providing a transient voltage suppressor defining a breakdown voltage upstream of the solid state switch.

The present disclosure uses a capacitive voltage divider to supply a voltage that can be more readily handled by main-stream semiconductor and magnetic components (generally less than 1000 volts). The divided system voltage, expected to be between 500 and 1000 volts, is then converted to a power supply voltage to be used by the measuring equipment. For safety reasons, this voltage is frequently required to be less than approximately 50 volts if it is delivered via a connectorized cable with exposed contacts.

An ultra-low clamping voltage Surge Protection Module (SPM) is disclosed which utilizes a depletion mode MOSFET (D MOSFET). The SPM may be part of a circuit or a device and includes a primary protection stage and a secondary protection stage, with the D MOSFET being connected between the two stages. The SPM may include a single D MOSFET, dual D MOSFETs, or multiple D MOSFETs and the primary and secondary protection stages may be implemented with a number of different components. The SPM using D MOSFET(s) exhibits improved surge protection over circuits using inductors.

A circuit arrangement for a surge protection device for protecting multiple DC or AC power lines. The circuit arrangement includes a plurality of DC or AC power line inputs, a negative potential or neutral input, a ground potential input, a surge protection component having one or more surge elements, a rectification circuit including a plurality of diodes, and an alarm circuit for receiving a status output from the surge protection component.

A drive for a mobile compressor includes EMI and transient protection circuits, second chokes, converters and an inverter. The EMI and transient protection circuits include respectively common mode chokes and at least one component. Each of the common mode chokes is configured to receive a first direct current voltage and is connected to first and second grounds. The at least one component is connected to a third ground. The first, second and third grounds are at different voltage potentials. The second chokes are connected downstream from the common mode chokes. The converters are connected to outputs of the second chokes and are configured to collectively provide a second direct current voltage to a direct current bus. The inverter is connected to the direct current bus and configured to convert the second direct current voltage to an alternating current voltage to power the mobile compressor downstream from the inverter.

A surge protection circuit includes: a power supply unit configured to supply first power, a filter unit configured to filter noise of the first power while a current corresponding to a surge flows through the filter unit, a motor unit provided with at least one motor, a control unit configured to control the motor unit according to an operation mode, and a rectification unit provided with at least one protection capacitor and configured to rectify the filtered first power into second power. The filter unit is connected with a ground to thereby apply the current to the filter unit through the ground. A first impedance is generated by the filter unit and the rectification unit and a second impedance is generated by the control unit and the motor unit and a value of the first impedance is less than a value of the second impedance.

An electronic initiation system for use with a firing panel may include an input connector, a plurality of electronic ignition circuits (EICs) operably coupled together in series, and an indicator operably coupled to an output of each EIC of the plurality of EICs. A first EIC of the plurality of EICs may be operably coupled to the input connector. The indicator is configured to generate an indication in response to an output of an EIC of the plurality of EICs satisfying a predetermined condition.

A multi-port solid-state circuit breaker system includes a first electrical power bus, a second electrical power bus, and a plurality of breaker legs conductively coupled with the first electrical power bus and the second electrical power bus in parallel with one another. Each of the plurality of breaker legs includes a first power semiconductor device coupled in series with a second power semiconductor device and an input/output port intermediate the first power semiconductor device and the second power semiconductor device. At least one of the first semiconductor device and the second semiconductor device includes an actively controlled switching device. A surge suppressor is conductively coupled in parallel with the plurality of breaker legs.

A lightning prewarning-based method for active protection against a lightning strike on an important transmission channel includes collecting meteorological element data, and establishing a transmission line-specific lightning strike probability prewarning model; using a maximum probability of a lightning strike prewarning level as a lightning strike prewarning level; performing equivalence calculation on a large-scale regional power system, using a minimum sum of a power loss risk cost and a regulation cost as an optimized objective function, and establishing a power flow transfer optimization model; and comparing a sum of a regulation cost and load power loss risk cost caused after the tie line is disconnected if regulation is performed before a lightning strike, and a load power loss risk cost caused if regulation is not performed, and when the regulation cost is not greater than the load power loss risk cost, performing regulation before the lightning strike.