Research On Real-time Simulating System Of Electrical Energy Metering

Under the new situation of developing smart grid, it is very urgent to study new problems on electrical energy metering affected by bidirectional power flow, bidirectional information exchange, real-time electrovalence and so on, which are brought by distributed energy sources, energy storages, electricizing stations, microgrids. It is a trend to charge for reactive energy metering, while nonsinusoidal reactive power theory hasn't unified at present, and reactive energy metering standard of nolinear load has still lacked, so there are some disputes about the problem of reactive energy metering. The graveness of harmonic pollution compels well done the metering and charge of harmonic energy becoming impendence. But, there isn't a system platform which can conveniently quickly and efficiently be used for testifing theory and algorithm research result at present.Based on the dSPACE platform, constructing a real-time simulating system of electrical energy metering was proposed in this thesis. Using the system can achieve testifying research results such as algorithm optimization design, harmonic analysis, harmonic metering, harmonic suppression, nonsinusoidal reactive power theory, reactive energy metering, reactive power compensation, impact load metering and special harmonic source simulation.Firstly, the basic idea of constructing a real-time simulating system of electrical energy metering based on the dSPACE platform was proposed in this thesis. The system structure and function were discussed in detail, and the way of using the system doing research was expatiated too. Designed and manufactured the input interface circuit of the system, to implement voltage and current transforming and sampling. In the input interface circuit, contrived all digital phase-locked loop(ADPLL) with high accuracy which can exactly track and lock the frequency of power grid, in order to meet integer-cycle sampling or reduce the degree of non-integer-cycle sampling, so decrease measurement error. The experimental results show that the input interface circuit can perform anticipative function, the ADPLL's locked accuracy exceeds 0.0002Hz, and the interface circuit can support various conditions'experiment research.Secondly, the thesis designed the method of building model and doing simulation based on the Simulink, and builded model and did experiment aimed at the active energy metering of three-phase three-wire circuit based on four numerical integration algorithms. The experimental results prove the feasibility of constructing the system's method and technology, and also prove the feasibility of using the system to do the high-level electrical energy metering research.Thirdly, discovered different manufacturer using different reactive power theory when had did reactive energy metering experiment aimed at the meters of internal and external different manufacturer. According to the theory definition, demonstrated the reasons of the sameness and difference of Fryze time domain reactive and universal definition of reactive using for reactive energy metering, and analysed their unification and non-coherence condition. Builded model and did experiment about the reactive energy metering of three-phase four-wire circuit. The theory analysis and the experimental results prove that:â‘ the theory definition of the active power is uniform, and its physical meaning is clear;â‘¡the reactive power definition of Fryze reactive theory and universal definition of reactive can apply in sinusoidal and nonsinusoidal state, and the two reactive power definitions are consistent and metering results are same when in symmetry, while the two reactive power definitions aren't consistent and metering results are different when in dissymmetry;â‘¢tke K2006 adopts classical sinusoidal reactive power theory definition, so it can't exactly meter reactive energy under nonsinusoidal state.