Analysis and Research on 500kV Bus Power Imbalance in Dispatching End UHV near Zone

Abstract

As a result of long distance of UHV AC transmission power transmission and fluctuations of tie-line power, large fluctuations exist in UHV near zone 500kV trend line, which seriously affects the calculation and assessment of bus efficiency in smart grid. In order to enhance the quality of the station fundamental data, through the research on sending the remote measurement acquisition principle, we found that measurement accuracy and Telemetry sent out of sync are main reasons. Combining with the current technology situation, it describes the basic ideas and implementation process of the two schemes, and points out the advantages and disadvantages of each scheme at the same time. For the traditional substation, it puts forward the Bay Control Unit (BCU) and Remote terminal units (RTU) reconstruction scheme based on GPS synchronization acquisition. BCU accepts GPS signal, sends the change telemetry data, RTU supports packing and sending important telemetry data under normal circumstances. When the BCU is abnormal or the synchronization is abnormal, RTU No packaging, only sends change telemetry data. So, important telemetry is fully synchronized under normal conditions, while data from abnormal BCU can also be effectively reflected in the SCADA. For new generation of smart substation, it raises a synchronous acquisition implementation based on Cluster Bay Control Unit (CBCU), the CBCU accept all SV message from the same bus, which can ensure bus power calculations and sent at the same time regardless of change trigger mode. Finally, it takes the UHV substation as a simulation model, the 500kV bus telemetry values as the basic data, finishes the bus imbalance simulation to verify the effectiveness of the scheme.