| Summary: | 碩士 === 臺北城市科技大學 === 機電整合研究所 === 103 === Present the regulation of distribution system voltage is mainly through the OLTC installed in the Taipower substation. In order to better regulation the voltage, Taipower wish to install FACTS units in its power network. Compared to the SVC, the company tend to use the static synchronous compensator STATCOM of have more quickly response speed, therefore, the focus of this thesis mainly on the STATCOM control technology.
When a STATCOM is installed with an on-load tap-changer OLTC, in general, a coordinated voltage control scheme, where the STATCOM responses for transient voltage variation and the OLTC for long-term voltage variation, is required to reserve the operating margin of STATCOM for emergency conditions and reduce the operating losses, the steady state output of STATCOM, and reduce the operation number of OLTC. Several control schemes for the aforementioned purposes are proposed, which includes a dual voltage feedback method which can provide high compensation output when there is an abnormal low voltage contingency in the upstream.
In order to expand the compensation area and improve the STACOM performance, the remote voltage signal measured by a phasor measurement unit PMU can be sent to STATCOM as the feedback signal. However, the PMU signal has the problem of time delay. In this paper, several Matlab/Simulink simulation scenarios are used to evaluate the effect of PMU time delay on STATCOM compensation performance. The simulation results show that the PMU time delay may affect the starting or ending time of STATCOM compensation output in response to the transient voltage events by the length of PMU time delay.
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