从加强主保护简化后备保护论变压器微机型继电保护装置

从加强主保护、简化后备保护的观点出发,论述了变压器的比率制动差动保护、标积制动差动保护、零序差动保护等主保护在使用中应注意的技术问题,指出差动保护灵敏度和快速性的提高必须建立在安全、可靠的基础上,提出了因电流互感器饱和与区外故障切除的暂态误差导致差动保护误动的具体措施。指出220kV电压等级以下的变压器可不装设零序差动保护,330kV和500kV自耦变压器可将零序差动保护作为接地故障主保护的辅助保护。在加强主保护的基础上,提出了简化后备保护的具体措施,着重讨论了各侧的短路后备保护、接地保护和各时间段的保护跳闸,以及地区小电源、并列运行变压器的后备保护配置、中性点间隙接地保护等问题。

Discussion on the Digital Transformer Protection from the Standpoint of Strengthening Main Protection and Simplifying Backup Protection

The digital transformer protection including main protection and backup protection is discussed from the standpoint of strengthening main protection and simplifying backup protection. Some technical problems of ratio restraint differential protection, the scalar product differential protection and zero-sequence differential protection etc. are analyzed. It is pointed out that increase in the sensitivity and quickness of differential protection must base on its stability, and a method of avoiding mal-operation caused by saturation and transient error of current transformer is provided. As the earth-fault assistant protection, zero-sequence differential protection can be applied to 330 kV and 500 kV auto-connected transformer, but it is not necessary for 220 kV and the lower voltage transformer. Several operable ways to simplify backup protection are given, referring to short-circuit backup protection, earth fault backup protection, and the configuration of local small power system, parallel transformer system, and neutral gap system.