Analys av påverkan från ökad mikroproduktion och installation av laddare för elfordon i lågspänningsnät

Sammanfattning: In Sweden, the number of rechargeable cars increases for every year. It is common to charge at home, for example because there is no need to wait for the vehicle to be fully charged.Charging at home takes place with low effects for longer time periods. The installation of micro production with photovoltaic systems is also increasing. Lidköping Elnät sees that the number of installations of chargers for electric vehicles and installation of micro production are increasing in the concession area and are expected to increase even more in the upcoming years. This study investigates the voltage variations that occur in an older and a newly constructed area with villas within the Lidköping urban area under normal load, as well as two future scenarios for micro production and chargers for electric vehicles. The work addresses which actions must be implemented in each area and what the actions cost.The voltage variations have been generated through calculations of the mentioned scenarios in the existing low voltage grid connected to the substation and the associated transformer in each area. Calculations on the low voltage grid at normal loads are based on consumption data take from Lidköping Elnäts’ system for debit measurement. In case of high production, a value is set for the photovoltaic systems that Lidköping Elnät considers as a normal size when a pre-registration of micro production is received. When charging electric vehicles, high consumption in the grid is assumed in the calculations. The voltage variations in the grid are added to the voltage variations occurring over the transformer to calculate the total voltage variations for the grid.Calculations of the total voltage variations in the grid for each scenario demonstrates that none of the points in the grid falls outside the limits allowed by the Swedish Energy Markets Inspectorate or European standard for voltage variations. At high production or high consumption the voltage increases or decreases for the weakest points fall outside the recommended limits for calculations. The high consumption scenario had the highest percentage differences form the reference voltage of 0,4 kV in both areas, which led to this scenario being used as the starting point for the development of actions.The actions developed reduce the voltage drops in both areas to be within the recommended limits of Swedenenergy, but also Lidköping Elnäts’ stricter limit for new connections. Lidköping Elnät is only obligated to implement an action if the voltage variations fall outside the limits set by the Swedish Energy Markets Inspectorate and the European standard or if complaints are received and poor power quality can be demonstrated.