| 摘要 |
The present invention is concerned with a method of distance protection of parallel transmission lines applicable both to series compensated and uncompensated electric power lines, using a distance relay. The method is characterized in that a pair of a flags (ff 1 , ff 2 ) are calculated for indication faulted and healthy circuits in parallel lines and in the same time a flag (Internal_Fault) for indication internal or external fault in parallel lines is calculated in independent way. Next gathering all calculated flags (ff 1 , ff 2 , Internal_Fault) an analyze of the value of these flags are performed and depending on the values of flags (ff 1 , ff 2 , Internal_Fault) and on their reciprocal relationship, a trip permission signal from the protection relay (4) is released and sent to the alarms devices or to the line breakers, or a block signal from the protection relay (4) is generated and sent to the users in order to protect parallel lines before damage. |
