Research Of Synchronized Phasor Measurement Technique For Distribution Networks

As the link between power transmission system and electric equipment, distributionnetworks have the characteristics of complex network structure, large numbers ofnodes, equipment widely distributed, and complex operation. Recent years havewitnessed a growing trend towards the development and deployment of distributedgeneration (DG). This trend in combination with new distribution generationtechnologies have profoundly changed the traditional analysis, design, controlparadigm of distribution networks. The trend of integrating a wide variety ofdistributed resources into distribution networks imposes significant challenges onoperating conditions such as reverse power flow, voltage rise, increased fault levels,reduced power losses, island mode operation, harmonic problem and stabilityproblems. To this end, it is important to have a real-time monitoring system fordistribution networks. There existing proven technique based on GPS and IEEE1588in the synchrophasor measurement for transmission networks. However it’s anentirely different scene in distribution systems, in which even there no systems ordevices that can be applicative. Nevertheless，a simultaneous measurement systemwill prove to be particularly important for distribution systems with high penetrationof renewables.This paper focus on the synchrophasor measurement for distribution networks andincludes the following aspects of work:(1) Contraposing the differences of transmission networks and distributionnetworks, in combination with the development of synchrophasor measurementtechnology this paper proposes a scheme of synchrophasor measurement fordistribution networks based on wireless communication, including the measurementsystem and measurement device.(2) Contraposing the shortcoming of current synchrophasor measurement methodsand applicability for DSP, an algorithm for synchrophasor calculation-DFT/FFT angleerror correction algorithm and the implementation of corresponding sampling method-frequency synchronous sampling are proposed in this paper. (3) Contraposing the inadaptability of current clock synchronization technology forsynchrophasor measurement in distribution networks, this paper proposes theapplication of wireless clock synchronization method. Take account the wirelesscommunication technology, this paper designs an implementation of the wirelessclock synchronization based on modified IEEE1588.(4) Based on the proposed scheme of synchrophasor measurement for distributionnetworks, this paper emphasizes on the implementation of the synchrophasormeasurement device. DSP is introduced for synchrophasor calculation and FPGA isintroduced for local clock maintaining and synchronization combining with GPS andwireless links. Finally, this paper does some tests of the device’s functions andprecision referencing to given standard and purpose of this design.