電氣工程及其自動(dòng)化畢業(yè)設(shè)計(jì)外文翻譯--一種特殊的預(yù)防電壓波動(dòng)的保護(hù)方案-在線瀏覽
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【正文】 Reference [7] proposed a simple method, which does not require offline simulation and training. The Voltage Indicator Predictor (VIP) method in [7] is based on local measurements (voltage and current) and produces an estimate of the strength / weakness of the transmission system connected to the bus, and pares it with the local demand. The closer the local demand is to the estimated transmission capacity, the more imminent is the voltage instability. The main disadvantage of this method is in the estimation of the Th233。venin?s equivalent for the system in that direction. Similarly the current flowing from other load bus (Figure 2) is used to estimate Th233。venin buses and 2. Equation (1)(4) can be bined into a matrix form: ?????????????????????????????????????12121111121211212112111121111211000000ththththththLththLZZZZZZZZZZZZZZ* ?????????????2121ththEEVV????????????2100EEII [5] 3 Using the first 2 rows in the system Equations (1)(4), the voltage on buses number 1 and 2 can be found as shown in Equation (6) below. From Equation (6) we can see that the voltage is a function of impedances. Note that the method assumes that all Th233。venin’s Parameters Th233。venin?s parameters within a particular data window, the algorithm can estimate properly but if a sudden large change occurs then the process of estimation is postponed until the next data window es in. ? The monitoring device based on the above principle can be used to impose a limit on the loading at each bus, and sheds load when the limit is exceeded. It can also be used to enhance existing voltage controllers. Coordinated control can 5 also be obtained if munication is available. Once we have the time sequence of voltage and current we can estimate unknowns by using parameter estimation algorithms, such as Ka lm an Filtering approach described [6]. stability margin (VSM) due to impedances can be expressed as ( ZVSM )。venin?s impedance. For normal operation the thevZ is smaller than loadZ (. it is outside the circle) and the system operates on the upper part (or the stable region) of a conventional PV curve [2]. However, when thevZ exceeds loadZ the system operates on the lower part (or unstable region) of the PV curve, indicating that voltage collapse has already occurred. At the maximum power point, the load impedance bees same as the Th233。venin?s equivalent for tracking the system trajectory. The algorithm is simple and easy to implement in a numerical relay. The information obtained by the relay can be used for load shedding activation at the bus or VAR pensation. In addition, the signal may be transmitted to the control centre,where coordinated systemwide control action can be undertaken. The algorithm is currently being investigated on an IEEE 30 bus system and results using the improved VIP algorithm will be reported in a future publication. References [1] , “On line monitoring of maximum permissible loading of a power system within voltage stability limits”, IEE proc. Gener. Transms. Distrib.,Vol. 150, No. 1, PP. 107112, January, 2020 [2] V. Balamourougan, . Sidhu and . Sachdev, “Technique for online prediction of voltage collapse”, IEE . Distrib., , No. 4, PP. 453460, July, 2020 [3] . Anizares, “On bifurcations voltage collapse and load modeling “IEEE Trans. Power System, Vol. 10, No. 1, PP. 512522, February, 1995 [4] Overbye and Demarco, “Improved Technique for Power System voltage stability assessment using energy methods“, IEEE Trans. Power Syst., Vol. 6, No. 4, PP. 14461452, November, 1991 [5] Smed Loof. T. Andersson, G. Hill and ,”Fast calculation of voltage stability index”, IEEE Trans. Power Syst. Vol. 7, No. 1, PP. 5464, February,
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