Research On Digital Multi-functional Power Meter Based On IEC 61850

With the rapid development of computer technology and network technology, digitalization and networklization have become a current in substation automation systems. Under the IEC61850 standard, digital substation has been extensively popularized with incomparable advantages.In connection with power measurement system in digital substation, a digital multi-functional power meter based on IEC61850 is deeply discussed in this paper. By analyzing the power meter located in the substation in the hierarchy, the dual bus network topology with process bus and substation bus is established. According to Part 7-3 and Part 7-4 of the IEC61850 standard, power meter information model includding data modeling and communication service modeling is carried on. Mechanisms of analog value sample Ethernet frame format and the mapping ACSI to MMS in substation level are also studied.The key to improve measurement accuracy of energy parameters is the measurement algorithm. An improved spectral leakage cancellation algorithm based on Fourier transform is used to measure the system frequency with a high accuracy. For the measurement of the harmonic voltage signal and current signal, scaled conjugate gradient training method is successfully used in linear artificial neural network and measurement result is excellent. For the reactive power measurement, the designed IIR digital filter is applied to approximate the -90 degree phase response of Hilbert transformer. Simultaneously, the frequency response of IIR filter is simulated by MATLAB, and the results show that IIR filter can do high-precision reactive power measurement.The design of the digital power meter includes hardware and software design. The hardware of the power meter is composed of digital signal processing circuit and two ways of fiber-optic Ethernet interface circuit. Digital signal processing circuit with TMS320F2812 DSP is used to calculating a huge number of energy parameters. The communication task between the process bus and the substation bus is fulfilled by two ways of fiber-optic Ethernet interface circuit, and each way of the circuit includes optic/electric converter, Ethernet media converter and Ethernet controller.