For the power distribution network line loss calculation, there are some problems, such as backward method, long calculation period, large workload and poor real-time performance. To this end, this paper proposes a real-time calculation method for distribution line loss based on dynamic three-phase unbalance, and a hardware device system with unbalanced phase sequence identification function, three-phase unbalance detection function and line loss real-time calculation function has been developed. The system uses a master-slave design based on the principle of wireless transmission. The slave collects standard three-phase current signals and transmits them to the host through wireless transmission. The host is installed on the low voltage side of the transformer in the transformer region, and the current signal of the transformer region is collected in real time. Unbalanced phase sequence identification, unbalance calculation, and line loss calculation based on dynamic unbalance are performed by comparing the current signals collected by the master and the slave. The above algorithm implementation process can be displayed online in real time. In addition to the core data processing and waveform display functions, the device also includes a battery power supply and management system, a signal storage and transmission system, and temperature measurement, and overcurrent and overvoltage protection. The test results of the device show that the device has the characteristics of convenient carrying, fast detection of three-phase unbalance, and accurate calculation of line loss. The device can monitor the running status of the distribution network transformer region in real time.
Real-Time Three-Phase Line Loss Calculation for Distribution Network Based on Electric Characteristic Measuring Terminal
