Study On Three-Phrase Multiloop Power Comprehensive Monitoring System Based On ATT7022B

With the rapid development of our economy, loading power increases rapidly.The demand for power become larger and larger, meanwhile, the customers make higher request to the quality of electricity. With the power electronics and other nonlinear equipments widely applied in power system, harmonic that can lead to the quality of power become worse and worse and sometimes even threat the safety of power and damage to electrical equipments has increasingly generated. The electricity monitoring instrument can record the abnormal parameters of supplying power, which can provide timely and reliable evidences for settling the problems.In the thesis, power monitoring device of three-phase multi-loop adopted the advanced electric power measurement technology, can measure the real-time power parameters, such as voltage, current, power etc. It contains many functions which not only can set the power measurement standards according to peak, flat, valley time of power but also transmit the recorded data to the host computer through RS485 and Ethernet, realizing centralized monitor to the high-voltage customers as many as 20.Both medium voltage grid and special mine grid adopt the operation mode of neutral line indirectly grounded. In the thesis, I also monitor and take note of electrical parameters in the three-phase and three-wire operation mode system. Combined with the hardware implementation, I put forward some theories about energy measurement in such an operation mode.The paper take the "Host CPU+slave measuring chip" method, the former manage the energy measurement chips ATT7022B while the latter record six or seven loop circuits of electrical signal. Application has proved that the study has many unique characteristics, on the one hand it can ensures the real-time and measurement precision in the comprehensive monitoring device, on the other hand, it also save the hardware resources as far as possible. Time-sharing multiplexing technology has been used in the software. In order to reducing the error, a particular algorithm applies to amend power value which is inaccurate during the sampling process by using the time-sharing multiplexing technology. In the final, I analyses the influences that all kinds of error affect on the measurement precision and then put forward an error compensation algorithm.I designed the three-phase multi-loop power comprehensive monitoring device based on the theoretical analysis. At the end, I correct the device precision by using Henan STAR calibration instrument. After operating for a period of time, the experimental results prove that three-phase multi-loop monitoring instrument has a high precision, good reliability, well stability in practical operation.