Accuracy of load and generation forecasts for the operational planning of power distribution systems

Operational planning in future power distribution systems will depend on load and generation forecasts as decisions and analyses will be performed in an increasingly coordinated manner at lead times. Forecasts on distribution level are significantly less accurate than on transmission level. The evaluation of forecast accuracy is therefore necessary to ensure system security. In this paper, forecast errors of wind power, photovoltaic power and load are evaluated for a medium-voltage grid region. Various influencing variables on forecast accuracy are examined. The evaluations show that forecasts in particular become worse for low aggregation levels and higher forecast horizons. In addition, the forecast error depends on characteristics such as the time of day or the magnitude of the forecast. For a secure system operation, forecast errors as well as their dependencies should be taken into account. Operational decisions should be made within the shortest possible lead time.