The submitted paper describes travelling wave fault location algorithm used for high voltage (HV) lines, based on wavelet transform, which was implemented in a prototype device and tested in laboratory conditions. Hardware and software parts of the fault locator, testing methodology and results are included in this paper.
Phasor Measurement Unit (PMU) performances are the basis for successful implementation of PMUs in power system security monitoring and control, and they are greatly affected by systematic errors caused by phasor estimation algorithm. In this paper, the Normal-Fitting Index (NFI) is proposed to identify PMU systematic errors in probability and statistics way. It reflects influences of systematic errors on PMU measurements. Besides, Weighted Least Square (WLS) curve-fitting method is applied here to identify systematic errors due to Discrete Fourier Transform (DFT) via analyzing the features of phasor estimations under dynamic conditions. Several PMUs are tested in laboratory and the results are used for analysis by the two methods above, which reveal that problems exist in PMU dynamic performances.
This paper presents the results of transient stability analysis in power system with high levels of photovoltaic (PV) penetration. In response to an increase of PV capacity, the capacity of conventional synchronous generator needs to be reduced relatively. This leads to the lower system inertia and the higher generator reactance, and hence the power system transient stability may negatively be affected. In particular, the impact on the transient stability may become more serious when the considerable amounts of PV systems are disconnected simultaneously during voltage sag. In this work, the potential impact of significant PV penetration on the transient stability is assessed by a numerical simulation using PSCAD/EMTDC.
With the development of smart grid, power quality is becoming a more important issue in distribution network. Distribution system could decide, or be obliged by users, to supply their users with different power quality levels at different prices. This paper presents a novel unified power quality conditioner configuration - Multiple Terminal Unified Power Quality conditioned (MT-UPQC) which is consisted of one series active filter and multiple shunt active filters. The MT-UPQC can compensate for voltage quality problems, harmonic currents fully and reactive current differently according to the requirements of users. The functions of the MT-UPQC as well as the adopted control algorithm are illustrated in the generalized way. A three terminal-UPQC (3T-UPQC) is built up on the PSCAD/EMTDC platform to undergo the detailed design, simulation and verification. The simulation result shows that the proposed approach is effective and flexible.
This work develops a microgrid stability controller to support microgrid switching its operation mode and provide DG units in the microgrid with the additional functionality of working in island mode without changing their control strategies. When microgrid works in grid connected mode, microgrid stability controller compensate power variation and reduces power fluctuation. When the main grid is not available, microgrid operates in island mode, microgrid stability controller provide output voltage and frequency reference for DG units. Its operation is analyzed by studying its control strategies, islanding detection techniques and black box arc model of circuit breaker at the Point of Common Coupling (PCC). Furthermore this paper analyzes its transient characteristics based on the dynamic performance of the microgrid during a fault in distribution network. Simulation and experimental results validates the feasibility of the microgrid stability controller.
