摘要:
The invention provides a method and apparatus for detecting communication channel delay asymmetry between transmission line protection devices. The method comprises: calculating, repeatedly, clock disparity between clocks of the protection devices and communication delays at different paths of the communication channel; comparing the latest calculated clock disparity and communication delays with previously calculated clock disparities and communication delays, respectively; determining a channel switching has happened if a change of the calculated clock disparity exceeds a first threshold, or a change of the calculated communication delays for any path exceeds a second threshold; and determining the channel delays as asymmetrical if a difference between the calculated communication delays of the different paths after the channel switching exceeds a third threshold.
摘要:
A synchronization method for current differential protection comprises: selecting a point on the transmission line protected by the current differential protection; measuring the current and the voltage of each of the terminals of said transmission line; calculating the compensating voltage at the selected point respectively according to the measured current and the voltage of the each terminal; detecting and calculating the synchronization error by comparing all the compensating voltages.
摘要:
A power conversion and distribution system detects faults by monitoring differential current and differential power at certain locations in the system. Current loss faults are detected based on the monitored differential current, and series arc faults are detected based on the monitored differential power. A system controller 16 may make the fault determinations and disable a power converter circuit 12 of the power conversion and distribution system in response to detection of a fault.
摘要:
Eine Schutzvorrichtung (100,300,400) für eine wenigstens eine Energiequelle (102), insbesondere mit geringer Überstromfähigkeit, eine Energieübertragungseinrichtung (103,303,403) mit wenigstens einem Netzstrang (104,105,106,304,404) und an jedem Netzstrang wenigstens eine angeschlossene Last (107) umfassende elektrische Energieversorgungseinrichtung (101,301,401), die selektiv eingegrenzte Bestandteile der Energieübertragungseinrichtung und die Energiequelle schützt, enthält je Netzstrang eine Lastschutzstufe (108,109,110,308), über die die wenigstens eine Last angeschlossen ist, eine Quellenschutzstufe (111) zum Abschalten der Energiequelle bei Unteroder Überspannung an der Energiequelle, in jeder Lastschutzstufe eine Messeinrichtung (150,151,350,351) zum Detektieren eines Strangstroms (IL,IL1,IL2,IL3) und einer Lastspannung (UL,UL1,UL2,UL3) sowie eine Schaltvorrichtung (153,353) zum Trennen des Netzstrangs von der Energiequelle, wenn der Strangstrom einen vorgebbaren Grenzwert überschreitet, und eine zentrale Steuerstufe (112,312) zum für jeden Netzstrang Vergleichen der Lastspannung mit einer Quellenspannung (UQ) und zum selektiven Trennen derjenigen Netzstränge, in denen zwischen der Lastspannung und der Quellenspannung eine Abweichung vorbestimmter Größe auftritt.
摘要:
A system and method for protecting a power system (102, 200). A generator (106, 202) is tripped in response to identifying a current on the generator (106, 202) that is greater than a first current threshold for a first time delay. The generator (106, 202) is also tripped in response to identifying the current on the generator (106, 202) that is greater than a second current threshold for a second time delay. The first current threshold is larger than the second current threshold and the first time delay is shorter than the second time delay.
摘要:
A power management and distribution system (10, 100, 200) includes a source block (20) having a source switch (22) and a power distribution line (21), wherein the power distribution line (21) includes a distribution switch (24). At least one load block (28, 102, 202) is in operable communication with the power distribution line (21) and having a plurality of load block power output lines, wherein each of the plurality of load block power output lines includes a load switch (32). Further included is a plurality of loads (34) each carried power by at least one of the plurality of load block power output lines. Yet further included is a protection logic unit (14) comprising at least one algorithm for comparing a power characteristic to a power characteristic threshold at a plurality of locations, wherein the protection logic unit selectively determines which of the source block switches (22), distribution switches (24) and the load switches (32) of the plurality of load block power output lines are opened based on at least one comparison.
摘要:
Logic circuitry for a directional comparison blocking protective relay scheme is described. A forward-reaching and a reverse-reaching protective relay (38) located at the local and remote terminals of a protected line segment (43) determine whether a fault is internal or external to the protected line segment. To carry out this function, the protective relays produce signals (64, 70, 68, 62) representative of fault location and communicate with each other via a communications channel (65). Processing the signals at each terminal is performed to determine the fault location and avoid tripping when the fault character changes. By using fault detectors to determine the existence of a fault, the logic at each terminal for combining the signals is simplified and security against false tripping is improved.