基于暂态注入法的数字化变电站系统级时间特性测试

Test of System-level Time Characteristics of Digital Substation Based on Transient Signal Injection

数字化变电站二次系统的单设备以及整体时间性能已有严格要求,且具有功能系统化的特点,但现有测试设备和思路仍然沿用传统变电站的思路,停留在单装置测试水平。为了适应新的需求,提出了一种系统级时间特性测试思路,以电子式互感器(ECT/EVT)、合并单元(MU)、保护装置、智能终端组成的保护功能子系统为被测对象,建立了一套基于暂态过程的系统级时间特性测试平台,在系统前端施加暂态电压电流模拟量,将被测系统内所有装置的输出信号全部纳入到测试系统,通过一次暂态过程试验,精确提取出MU的暂态延时、报文抖动时间、保护动作时间、智能终端动作延时、整组动作时间等系统整体时间特性和所有单装置环节的时间特性。分析了信号变换、模数转换、参数计算、报文到达时刻标定、开关量变位检测等主要误差环节,并给出了减小相应误差的办法。建立了实验室测试系统,试验验证了方案的有效性。

There are strict requirements on time performance in digital substation secondary system, which has the characteristics ofsystematic function. However, current test equipment and method still use traditional ideas, which stay in the level of testing for singledevice. In order to meet the new needs, a system level time characteristics testing idea is presented. The electronic transformers（ ECTIEVT）, merging unit（MU）, relay protection device, intelligent terminal are formed protection subsystem, which is the object to bemeasured, and a set of system level time characteristic testing platform is set up basing on transient process. Transient voltage and cur-rent analog signal are applied to merging unit front end, all device output signals are brought into the test system. Through a transientprocess test, the time characteristic such as merging unit transient delay, packet jitter, protection action time, intelligent terminal ac-tion delay and action time of the whole group and single units are extracted exactly. The main part of error of signal conversion, analogdigital conversion, parameter calculation, packets time calibration, switch position change detection are analyzed , and the solution todecrease corresponding error are gived. A testing system is established in the laboratory, and its effectiveness is proved by test.