Abstract: An electrical fault detector is shown for installation in electrical network (101) of the type comprising a first voltage source (104) and a second voltage source (107), each of which have a respective positive rail (105,108) connected by a positive concentrator (110) and a respective negative rail (106,109) connected by a negative concentrator (111). The detector comprises an inductor (112) for location in one of: the positive concentrator between the connections of the positive rails thereto, and the negative concentrator between the connections of the negative rails to thereto. The detector also comprises a fault identification device (113) configured to monitor the voltage across the inductor, and generate a fault signal in response to the voltage across the inductor exceeding a threshold.

Abstract: A method of determining the location of a fault within a first inductive part of an electrical circuit, including a voltage source, first inductive part and second inductive part. A shortened circuit created by the fault includes the voltage source, a portion of the first inductive part and the second, connected in series. The fault occurs across first and second points in the first inductive part. The length of first inductive part between a positive terminal and first point is substantially equal to the length of first inductive part between a negative terminal and second point. The voltage source supplies a known voltage Vs when the fault occurs and the second inductive part has a known inductance L2 when the fault occurs. The method takes advantage of the initial transient response of the circuit to determine the inductance of the portion of the first inductive part in the shortened circuit.

Abstract: A protection system is provided for an electrical power network. The system has one or more circuit breaker arrangements which on activation isolate electrical faults within the network, and one or more fault detectors. The or each fault detector measures an inductance of a respective section of the network. The system is configured to activate one or more of the circuit breaker arrangements in response to measured inductances which are indicative of a fault.

Abstract: A DC electrical power system has a power generator converter system, a positive supply rail extending from the converter system, a negative supply rail extending from the converter system, and a midpoint earthing arrangement operatively connecting to the supply rails. The earthing arrangement is connected to earth by a solid earth connection. The network further has a first protective device on one of the supply rails which in case of a fault is operable to interrupt current flowing on that rail, and a second protective device on the earthing arrangement which in case of a fault is operable to interrupt current flowing to earth through the solid earth connection.

Abstract: Previously, electrical power systems have been analyzed to provide theoretical fault levels values for different zones of an electrical power distribution system based upon a worse case scenario. However, existing electrical loads will in practice provide a more adaptable and higher fault level. By monitoring and identifying an I-V characteristic upon switching electrical load in practical operation an actual default level at particular nodes in a power distribution system is determinable. In such circumstances decisions with regard to the connectability of further electrical generators or loads at particular parts and zones of an electrical power distribution system can be quantified by reference to the actual fault level rather than the theoretical worse case scenario level and therefore avoid unnecessary upgrading of transmission equipment or denying access to the electrical power system.

Abstract: Safe operation of electrical power distribution systems necessitates consideration of the fault level in terms of the potential for electrical current flow upon an earth or other fault within the electrical power distribution system. Previously, electrical power systems have been analysed to provide theoretical fault levels values for different zones of an electrical power distribution system based upon a worse case scenario. However, existing electrical loads will in practice provide a more adaptable and higher fault level. By monitoring and identifying an I-V characteristic upon switching electrical load in practical operation an actual default level at particular nodes in a power distribution system is determinable.