220kV Bus Load Characteristics Analysis And Forecasting

Bus load forecasting results are the realization of the foundation of leanoperation management, and are the premise of carrying out security check andcongestion management, electric power and energy balance and maintenanceplanning. Carrying out bus load forecasting can change the way of power gridsecurity check, and improve the accuracy of the security check and the congestionmanagement, together with the grid online security and stability analysis level.This paper analyzed the220kV bus load characteristics in Hunan provincePower Grid, and put them into different categories by using fuzzy C-clusteringmethod. Then the paper selected classical buses from each category within Changshaarea and studied them in detail. The correlations between bus load and such factorsas weather, the types of days were considered, and corresponding loadcharacteristics are noted for further reference.With the meteorological and day-type factors thoroughly considered, this paperproposed a new bus load forecasting method based on improved gray model. Thisnew method used weighted exponential method to transform the original bus loadsequence so that we could weaken the impact of outliers, fully utilize inherent usefulinformation, reduce the randomness of the sample data and strengthen the originalsequence trend. Because the buses severely subjected to the meteorological andday-type factors, this paper selected several most similar day loads as historicalsamples by building classic day feature vector. While there was a weak affection ofthese factors, this paper, by applying the weighted moving average method, usedsuch a way so that recent day loads samples were given a bigger weights and oldersamples smaller weights. Example had shown that the classification was reasonableand necessary, and of high prediction accuracy.However, the buses of each substation are numerous and the load characteristicsare different from each other. Therefore, the workload of prediction is heavy and theaccuracy of the prediction is very low. In this paper, a centralized bus loadforecasting system was developed which supports the security checking of powergeneration program management according to the practical situation of bus load andthe expectations of bus load prediction. The software was developed withMicrosoft.NET platform and Microsoft SQL Server database, using the most advanced and sophisticated multi-layer system of Browser/Server (B/S) structurewith the basis of the existing load forecasting system. The centralized integratedsystem consists of bus load forecasting unit, load statistics and analysis unit,prediction and assessment-based assessment unit, data collection unit, forecastingdata reporting unit, basic information management and systems managementprocesses unit which provides security checking for generating schemes andscheduling fine management to provide support of data and technical protection.Advanced prediction strategy was proposed which can improve the predictionaccuracy.