发电机滞后无功保护故障原因分析及改进措施

针对因我厂9000kW 发电机滞后无功保护故障引发的全厂停电事故,论述了该发电机滞后无功保护动作原理,并对其故障原因进行了理论分析,提出了改进措施。

浅论无功保护参数在通信用柴油机和UPS匹配中的重要性

随着IDC机房的发展,UPS系统在机房电源中比重的加大,柴油发电机组和UPS系统的匹配问题越发突出。文中通过对某个数据中心柴油发电机组在带UPS系统负载时出现的故障进行分析,论述了一个日常被忽略的柴油发电机组中"无功保护"参数的设置在柴油发电机组和UPS匹配过程中的重要性,对实际工作具有一定的指导意义。

GDH—10型无功耗保护器在烘棉设备上的应用

烘棉设备是纺丝后处理的重要设备,圆网的直径为1400mm,转动惯量较大,因而启动较困难;并且启动时间较长,大电流延续时间较长。若采用双金属片式热继电器作过载和缺相保护,则不能使设备可靠启动。其原因是:热继电器是根据通过双金属片的电流产生热量,使其弯曲而动作的。

Design of Capacitor Bank in Parallel to Photovoltaic Power Plant

The purpose of the paper is to develop a solution for application of PV （photovoltaic） generators in MV （medium voltage） distribution system without unacceptable voltage changes due to drops of PV power output. The proposed solution includes operation of PV with predetermined leading power factor and addition of a capacitor bank in parallel to PV plant in order to compensate the reactive power absorbed by the PV inverters. The analytical expression of required power factor angle is derived. Adding a capacitor bank in parallel to PV power plant may pose a problem because of space limitations. The dimensions and cost of small MV capacitor banks depend significantly on the capacitor bank protection against internal faults. Application of the developed negative-sequence current difference method for the unbalance protection of the capacitor banks enables to achieve a compact and cost-reduced design of the banks connected in parallel to PV power plants. A real-world example of operation of the PV plant in parallel to the capacitor bank with the novel protection scheme is described.

1000kV南阳变电站110kV侧的继电保护配置

1000kV特高压南阳变电站110kV侧低压无功补偿设备与传统超高压变电站的低压无功补偿设备相比,在设备原理、设备容量、接线方式、保护原理和控制方案方面存在较多的特殊性和创新性。介绍了大容量并联电容器组双桥差保护接线的方案;110kV新型负荷开关的应用使110kV系统的无功设备保护跳闸采用2级出口,失灵保护采用的2级失灵方案;母线死区故障采用特殊跳闸方案;特高压变电站站用变容量相对较小,针对电流互感器(current transformer,CT)配置、继电保护定值整定、系统调试等方面出现的新问题提出了解决方案。鉴于南阳站站用电系统接线方式的特殊性,提出了110kV站用变差动保护范围的优化方案。