A connection-and-protection device having two capacitively connected conductors respectively connected in use to a supply cable at one end and a load cable at the other end is provided, the connection and protection device including a connection terminal for connection to either of the supply or load cables, a pair of cable terminals for the respective capacitively connected conductors, a direct connection within the device between the connection terminal and one of the pair of cable terminals, the other of the pair cable terminals not normally being connected to the connection terminal and means for connecting the other of the pair of cable terminals to the connection terminal to protect the capacitive connection of the two conductors, if the voltage between the pair of cable terminals exceeds a threshold and event detection means comprising means for detection the voltage between the pair of cable terminals exceeding a threshold.

This application describes methods and apparatus for the safety and protection of capacitor units suitable for medium and high voltage applications, for instance within switching modules (400) of a voltage source converter as may be used for HVDC or FACTs. The capacitor unit (300) has a housing (201) within which is a capacitor comprising a plastic film dielectric material, for instance a winding (100) of first and second plastic films (101, 102) with metal coatings (103, 104). A pressure sensor (302) is configured to detect if the pressure in the housing exceeds a first pressure level and a pressure relief valve (304) is configured to vent gas from the housing if the pressure in the housing exceeds a second pressure level which is higher than the first pressure level.

This application describes methods and apparatus for the safety and protection of capacitor units suitable for medium and high voltage applications, for instance within switching modules (400) of a voltage source converter as may be used for HVDC or FACTs. The capacitor unit (300) has a housing (201) within which is a capacitor comprising a plastic film dielectric material, for instance a winding (100) of first and second plastic films (101, 102) with metal coatings (103, 104). A pressure sensor (302) is configured to detect if the pressure in the housing exceeds a first pressure level and a pressure relief valve (304) is configured to vent gas from the housing if the pressure in the housing exceeds a second pressure level which is higher than the first pressure level.

A frequency converter includes a storage element for storing electrical energy and a detector connected to the storage element and including a pressure sensor and a temperature sensor. The detector detects a physical variable in immediate vicinity of the storage element and provides a signal in accordance with an electrical resistance of the detector when a predefinable change over time of the physical variable is exceeded, with the electrical resistance representing an output of the detector. A housing encloses or substantially encloses the detector and the storage element. Communicating with the detector is an evaluation facility to detect the predefinable change over time of the physical variable. The evaluation facility and/or the detector is/are connected to a higher-level security system designed to decouple and/or to divert the electrical energy from the storage element when the predefinable change over time of the physical variable is exceeded.

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.

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.

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.

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.

An ignition apparatus for a spark gap arrangement containing at least a first and a second ignition capacitor for voltage division of a voltage between a first and a second electrode of the spark gap arrangement. A first trigger spark gap is arranged in a first parallel branch with respect to the first ignition capacitor, and a second trigger spark gap is arranged in a second parallel branch with respect to the second ignition capacitor. A first ignition resistor is disposed in the first parallel branch, wherein a first potential point between the first ignition resistor and the first trigger spark gap is connected to an ignition electrode of the second trigger spark gap. Furthermore, a spark gap arrangement containing the ignition apparatus, an arrangement containing a high-voltage device and the spark gap arrangement for protecting the high-voltage device, and a method for igniting the spark gap arrangement are disclosed.

A protection and monitoring system, device, and method for an electric power system, including a capacitor bank having multiple strings in each phase, voltage and current measuring devices, and relays to protect this capacitor bank. Each string can have multiple capacitor units and each unit can consist of multiple capacitor elements. The method may include: determining steady state operating condition using the obtained current and voltages, calculating and storing present time impedance value of each string into memory, calculating the string per unit impedance incremental quantity, detecting capacitor element failure based at least in part on this incremental quantity and calculating number of failed capacitor elements for each event, accumulating the number of failed capacitor elements, and performing a protection action when healthy capacitor elements are subject to an overvoltage limit. The method may be inherently immune or otherwise insensitive to capacitor variations due to aging, temperature change, instrument transformers errors, inaccuracy in data acquisition, and inherent manufacturing unbalance.