Abstract: A differential protection system including a plurality of inputs power cables for transfer of power from electric power generators, such as wind power generators, to an output cable. Each input and output power cable is provided with a respective circuit breaker. The protection system includes a plurality of protection equipment unit each being adapted to be arranged at a respective one of the input cables or at the output cable, each protection equipment unit including a measuring unit for measuring the current and voltage of the cable, and including a control unit being operatively connectable to the circuit breaker of the respective power cable for selectively tripping the circuit breaker when the protection system discovers a differential fault. The protection system includes a charging current compensator for compensating the differential protection for charging currents of the cables of the transfer system.

Abstract: A differential protection system including a plurality of inputs power cables for transfer of power from electric power generators, such as wind power generators, to an output cable. Each input and output power cable is provided with a respective circuit breaker. The protection system includes a plurality of protection equipment unit each being adapted to be arranged at a respective one of the input cables or at the output cable, each protection equipment unit including a measuring unit for measuring the current and voltage of the cable, and including a control unit being operatively connectable to the circuit breaker of the respective power cable for selectively tripping the circuit breaker when the protection system discovers a differential fault. The protection system includes a charging current compensator for compensating the differential protection for charging currents of the cables of the transfer system.

Abstract: A protection device for a power network performs a method to align measuring times of first and second measurements of an electric quantity, taken at different ends of a power network line transmitted with measuring times via a telecommunication network. In the method, a send transmission time from the local to remote end of the line and a receive transmission time from the remote to local end of the line are determined based on time signals from internal clocks. After a global time reference to synchronize the internal clocks is lost, a clock drift is determined between the internal clocks. The measuring times of the first and the second measurements are aligned using the send and receive transmission times as well as the clock drift. A sudden change in the clock drift is determined in order to recognize a route switching in the telecommunication network and the clock drift is corrected.

Abstract: A differential protection method in a power network for determining type of fault occurring within the power network. The power network includes a protected object having two or more ends, and a current differential protection device and a current transformer are arranged at each end. The method includes the steps obtaining, at a first end of the protected object, measured values from a second end of the protected object; comparing, at the first end, changes in measured values taken at the first end with changes in the measured values obtained from the second end; and determining, upon the step of comparing changes in measured values showing differing results, type of fault occurring within the power network.

Abstract: A differential protection method in a power network for determining type of fault occurring within the power network. The power network includes a protected object having two or more ends, and a current differential protection device and a current transformer are arranged at each end. The method includes the steps obtaining, at a first end of the protected object, measured values from a second end of the protected object; comparing, at the first end, changes in measured values taken at the first end with changes in the measured values obtained from the second end; and determining, upon the step of comparing changes in measured values showing differing results, type of fault occurring within the power network.

Abstract: A protection device for a power network performs a method to align measuring times of first and second measurements of an electric quantity, taken at different ends of a power network line transmitted with measuring times via a telecommunication network. In the method, a send transmission time from the local to remote end of the line and a receive transmission time from the remote to local end of the line are determined based on time signals from internal clocks. After a global time reference to synchronize the internal clocks is lost, a clock drift is determined between the internal clocks. The measuring times of the first and the second measurements are aligned using the send and receive transmission times as well as the clock drift. A sudden change in the clock drift is determined in order to recognize a route switching in the telecommunication network and the clock drift is corrected.

Abstract: A robot controller including a control unit and a portable operating device (TPU) for teaching and manually operating the robot. The TPU includes safety equipment, a safety TPU-part having a first communication unit and a main TPU-part having a third communication unit. The control unit includes a safety control part having a second communication unit and a main control part having a forth communication unit. The first and second communication units are arranged such that they form a first communication channel for transferring communication data including information regarding the status of safety equipment from the TPU to the control unit. The third and fourth communication units are arranged such that they form a second communication channel for transferring general communication data between the TPU and the control unit.

Abstract: A protective means for a series capacitor in a high-voltage network comprises a voltage-dependent resistor (varistor) arranged in parallel with the series capacitor, a spark gap arranged in parallel with the varistor for shunting the latter when it becomes overloaded, a current-sensing member, for example a current transformer, for sensing the current through the varistor, an energy absorption detector for sensing the temperature of the varistor, and a pulse transformer electrically or magnetically connected to the current-sensing member, for triggering the spark gap. During normal operation of the network and the series capacitor the current-sensing member is short-circuited by a normally closed switching device.