Voltage sag is certainly transmitted in the power grid, both the grid and the user are urgent to study and control it. As a precondition to solve the problem of voltage sag , it is necessary to study the detection method. The causes of induction motor starting and transformer energizing are analyzed , and the detection method of short duration power quality disturbances based on the S-transform is used , the required datum are extracted from results of S-transform, in order to analyze the depth, phase jump, continuous time and harmonic content between two kind of disturbances. The simulation results show that the method is good for the detection of voltage sag , and it is high practical value of applying on the offline analysis of waveform data of voltage sag.%电压暂降在电网中具有一定的传播性，无论从电网还是用户都迫切需要对电压暂降进行研究和治理。作为解决电压暂降问题的前提，需先对其检测方法进行研究。分析了感应电动机启动和变压器激磁两种扰动情况引起电压暂降的原因，在此基础上采用了基于S变换的短时电能质量扰动检测方法，从S变换的结果中提取出所需数据，并以此来对上述两种扰动情况的暂降深度、相位跳变、持续时间和谐波含量进行分析。仿真结果表明，该方法很好地实现了对电压暂降各特征量的检测；在对暂降录波波形数据进行后续离线分析应用方面具有较高的实用价值。
展开▼
