Abstract The time-current curve type and the considered fault locations influence the optimal coordination of directional overcurrent protections. It is shown that curve type can determine the feasibility of having solutions and the feasibility of obtaining reasonably low trip times. It is also shown that constraints for faults near to the main relay location must be complemented with those of other fault locations. In general, the use of Extremely Inverse curves implies a faster protection in the analyzed cases. This is because this coordination depends on the ratio between the currents seen by each relay, and Extremely Inverse curves have the greatest inclination in time-current graphs. The backup action for faults near to the remote line end of main relays can be very slow with Extremely Inverse curves in some cases; therefore, an analysis of benefits and drawbacks of using each curve type should be performed in each analyzed case.

中文翻译：

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过流功能曲线类型和故障分析位置对方向过流保护优化协调的影响

摘要 时间-电流曲线类型和考虑的故障位置影响方向过流保护的最佳协调。结果表明，曲线类型可以确定解决方案的可行性以及获得合理的低行程时间的可行性。还表明，对靠近主继电器位置的故障的约束必须与其他故障位置的约束相辅相成。通常，在分析的情况下，使用极逆曲线意味着更快的保护。这是因为这种协调取决于每个继电器看到的电流之间的比率，并且极逆曲线在时间-电流图中具有最大的倾斜度。在某些情况下，主继电器远程线路端附近故障的备用动作可能会非常缓慢，并带有极逆曲线；所以，