دانلود رایگان ترجمه مقاله برآورد دینامیک پایداری سیستم توان در پیاده سازی های مختلف فیلتر کالمن (نشریه IEEE 2014)

برآورد دینامیک پایداری سیستم توان در پیاده سازی های مختلف فیلتر کالمن

Dynamic Estimation of Power System Stability in Different Kalman Filter Implementations

Abstract

Voltage collapse is still the biggest threat to the transmission system. There are many approaches that have been explored to predict the point of voltage collapse. However, it is still lacking of information that related to current system state. With the advancement of Phasor Measurement Units (PMUs) technology, it provides an alternate pathway to improve the existing power system state estimation. Hence, it was of interest to develop better methods that could give a preliminary warning before the voltage collapse. This paper concerns for the development of real-time system monitoring methods to give a timely warning in the power system. The algorithm to predict the points of collapse is based on the assumption that voltage instability is closely related to the maximum load ability of a transmission network. Therefore, the Thevenin impedance is equalled to the apparent load impedance at the points of collapse. Numerous methods such as Discrete Kalman Filter (DKF), Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) are being implemented into the realtime voltage instability predictor to track the Thevenin parameters. The test results are tested on Malaysia’s power system 132 kV – ۲-bus and 10-bus systems. The results are compared based on the early-warning index of voltage collapse. The results of DKF method are set as the reference for comparison purpose between EKF method and UKF method. The test results shown that EKF method provided better results by decreasing of 0.1169 p.u. for 2-bus system and 0.0338 p.u. for 10-bus system. In the meanwhile, UKF method provided increasing values of 0.4262 p.u. for 2-bus system and 0.1522 p.u. for 10-bus system. The overall purpose of this research is to develop methods that in provide early warning for an emerging stability problem. In order to achieving the research’s objectives, derivation of the index for early warning of the point of collapse is completed. The performance of each method used throughout this research is based on the analyzed results for the points of voltage collapse.

۱ Introduction

With the growing of demand in power system, voltage instability problem has become a challenge to power system operator. Load growth without a corresponding increase of transmission capacity has brought many power systems closer to their voltage stability boundaries, which leads to voltage instability problems increase. Moreover, the stable system contributes to reliability and reduction in system loss. Hence the voltage instability problem has received a lot of attention not only from researchers but also from the industry. Thus, a continuous real-time voltage margin monitoring system is required to predict the distance from the point of voltage collapse.

The Malaysia power system is equipped with Phasor Measurement Units (PMUs). The implementation of the PMU technology in real power systems is under the process currently. By referring to the announcement on the increase of electricity tariff as in [1], the continually increasing in load demand and fuel cost leads to urgent needs to improve operational efficiency’s utilization of transmission and distribution assets and reduction of losses. Therefore, Tenaga Nasional Berhad-Transmission (TNB-T) and TNB-Research (TNB-R) have joint collaboration in a 5-years research and development project on Wide-Area Intelligent Systems (WAIS) to enhance security and reliability of the power system network, and hence to provide system operators with realtime information on proximity of the system to voltage collapse as stated in [2].

The existing transmission lines have been equipped with the protection and countermeasure systems to prevent from a collapse. Hence, the actual data from the applied PMUs will never find any collapse in the system. Therefore, fault occurrence or tripping on the bus will be created in the simulation by using Real-Time Digital Simulator (RTDS). The PMUs simulated data obtained from TNB-R are in the form of voltage and current, which refer to its magnitude and angle. For the time being, TNBR is using the latest PMUs technology that able to measure 50 samples per second. The experimental performance of simulation was conducted at TNB-R with the 132 kV system with 2-bus and 10-bus systems. The limitation of this project is due to the communication channels at some TNB substations of interest are not fully configured, thus the measurements based on actual data streams are still impossible at the moment. Therefore, the results shown are based on input from simulations.

This paper will address the overviews of voltage stability in the next section. Third section will include the development of methodology and technique used in this research. The fourth section will show the results and discussion. The conclusion is shown in the last section.