This paper investigates the potential of using battery energy storage systems in the public low-voltage distribution grid, to defer upgrades needed to increase the penetration of PV. A multi-objective optimization method is proposed to visualize the trade-offs between three objective functions: voltage regulation, peak power reduction and annual cost. The method is applied to a near-future scenario, based on a real residential feeder. The results provide insight into the dimensioning and the required specifications of the battery and the inverter. It is found that an inverter without batteries already achieves part of the objectives. Therefore, the added value of batteries to an inverter is discussed. Furthermore, a comparison between lithium-ion and lead-acid battery technologies is presented.

Abstract-Electrical energy storage services can bring benefit to multiple stakeholders in the distribution grid. Energy storage owners maximize their profit on an external energy market. This can cause a conflict with the distribution system operator because a grid is designed in terms of peak power, not energy. The subject of this paper is a optimization method for the siting and sizing of energy storage in distribution grids. The optimization is implemented multi-objective as to visualize the trade-offs between storage stakeholders and distribution system operators.

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Abstract-This paper investigates the numerical accuracy of currently employed methods for electromagnetic transient simulation with power electronics. Existing tools often employ the second-order accurate trapezoidal method for numerical integration. However, solution techniques employed to facilitate ideal power electronic switches do not always preserve this second-order accuracy at switch events. As a result, the step size required to achieve the desired level of accuracy is often smaller than expected, affecting simulation speed. Therefore, this paper aims to assess and improve the trade-off between step size and accuracy. First, currently employed solution techniques are reviewed by deriving asymptotic estimates of the rates at which approximation errors decrease as the step size reduces. Afterwards, a benchmark method is proposed which preserves second-order accuracy at switch events. The tools EMTP-RV and PSCAD are compared with this benchmark method for elementary circuit examples. The results demonstrate the potential to improve accuracy, by several orders of magnitude in some cases, without increasing the number of linear systems to be solved.