Siemens Aktiengesellschaft

Matthias Gross

Torsten Kerger

Robert Matussek

Andreas Regenbrecht

Torsten Schumacher

Sven Krueger-Gramatte

A differential protection device monitors a first object to be protected in an electrical energy supply network. The differential protection device has a measuring unit configured to acquire measurement values at one end of the first object to be protected, a communication unit configured to exchange measurement values with a differential protection device arranged at another end of the first object to be protected, the communication unit has a physical interface for transmitting and receiving the measurement values, and an evaluation unit configured to form a differential value and to generate a fault signal indicating a fault with regard to the first object to be protected if the differential value exceeds a predefined threshold value. Ideally, the differential protection device is configured to monitor further objects to be protected and to exchange respective further measurement values with regard to each further object to be protected.

Differential protection device and protection system for monitoring objects to be protected in a power supply network

A differential protection method for monitoring a line of a power grid. Current phasor measured values are captured at the ends of the line and transmitted to an evaluation device which is used to form a differential current value with current phasor measured values temporally allocated to one another. Time delay information indicating the time delay between local timers of the measuring devices is used for the temporal allocation of the current phasor measured values captured at different ends, and a fault signal indicating a fault affecting the line is generated if the differential current value exceeds a predefined threshold value. The reliability of the time synchronization is further increased by forming a quotient of the current phasor measured values to form an asymmetry variable, that is used to check a transit time difference of messages transmitted via the communication connection in different directions.

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Berlin, Germany

Matthias Gross