Requirement
A distribution system operator wanted to assess the impacts on a urban grid of massive integration of decentralized power generation (solar plants and hydropower) and new consummers (electric vehicles, high power electrical PAC ...) .
The studied urban distribution grid is composed with three MV loops fed by two HV substations. Each loop feeds a dozen HV/LV distribution stations for industrial and residential uses.
This prospective study was therefore to evaluate the maximal penetration rate of renewable power and new consumers. The main issues to be addressed are the network stability and power quality,.This prospective study was therefore to evaluate the maximal penetration rate of renewable power and new consumers. The main issues to be addressed are the network stability and power quality.
Realization
CAPSIM has made a digital model with DIgSILENT Power Factory software for static and dynamic simulations of the network.
Firstly, an audit of the existing network was performed with this model in order to control the voltage quality and existing design margins. Especially, to analyze the voltage plan (existing margins on the voltage fluctuations), the short-circuit currents and harmonic distortion level. An analysis of this audit enabled to identify distribution substations which are the most sensitive to the connection of decentralized power plants.
Secondly, three scenarios with different renewable energy penetration rates were defined in order to assess, from the network model established by 2020, the impact of the connection of power productions on the power flows and voltage quality of network.
The model, built from current network’s consumption data included changes planned on the network :
- a new MV distribution loop intended for supplying residential buildings and electric vehicle charging stations
- changes in consumption of industrial sites
- 4 photovoltaic power plants
- 1 hydropower plant
Dynamic simulations were performed for a period of 24 hours in order to represent the variations of consumption on one hand and production (related to photovoltaic energy) on the other. Sunlight conditions, varying according to the seasons and the days, were also taken into account
The analysis of the results of the scenarios was performed in order to check :
- The independence of the network in front of fluctuating production even with an extreme production / consumption ratio
- The design of the equipment to feed the network with all the planned changes
- Compliance with quality voltage constraints
- The stability of the network with a penetration rate of renewable energy at maximum views of planned projects
Results
This study was useful to :
- Achieve a dynamic model of existing and future network
- Analyze the impact of new consumer and ppower generation projects
- Check the design margins of the network for the connection of these projects
- Establish general rules for the maximal penetration rate of renewable energy on the grid
Daily photovoltaic production profiles
