主变复压过流保护的电压整定及灵敏度校验

Voltage Setting and Sensitivity Checking of MT Complex Voltage Overcurrent Protection

主变复压过流保护是电厂主变相间后备保护的标配。长期以来,由于该保护十分常用,原理简单明了,因此继电保护人员常在整定计算过程中直接给出经验值,不去校验保护的灵敏度,导致某些变压器的灵敏度不满足标准要求,造成保护不能快速、及时、准确地动作,严重威胁变压器主设备的运行安全。通过一起主变复压过流保护的电压整定案例,阐述了某些情况下低电压灵敏度不满足要求的现象,提出解决问题的措施,完善了保护方案,修正了保护的定值,使保护能更有效、快速、准确地切除故障,保护电气主设备,以便更好地服务于发电企业的安全生产工作。

The complex voltage overcurrent protection is a standard configuration for inter-phase backup protection of main transformers in power plants.For a long time,due to the common use of this protection and its simple and clear principle,relay protection personnel have been prone to laziness,negligence,and carelessness in the setting calculation process.They directly provide empirical values rather than check and recalculate sensitivity of the protection.This results in substandard sensitivity of some transformers and consequently incompetence of protection mechanisms in promptness and accuracy,seriously threatening operational safety of transformer main equipment.This paper reveals the phenomenon of inadequate sensitivity in some cases through a voltage setting case of complex voltage overcurrent protection,proposes measures to solve the problem,perfects the protection scheme,corrects the protection setting,and enables the protection to more effectively,quickly and accurately island faults and protect electrical main equipment.