A NEW SMART DISTRIBUTION TRANSFORMER WITH OLTC FOR LOW CARBON TECHNOLOGIES INTEGRATION
Over the past decade, there has been a rising awareness of use of renewable energy sources (RES) and the extension of such matters as reduction of CO2 emissions and energy consumption becoming worldwide issues. Low carbon technologies (LCT) such as electric vehicles (EV) and distributed generators (DG) can contribute to fulfil the objectives of limiting global warming. The development of a new compact smart distribution transformer with an On Load Tap Changer (OLTC) in collaboration with ENEDIS Technical Direction, keeps the voltage stable in distribution grids by compensating voltages instabilities in the medium voltage (MV) and can help the integration of LCT by regulating the voltage automatically to cope with the voltage fluctuations generated by new loads and DG in the low voltage (LV) side of the electric network. The smart transformer operation has been tested first in a new 'laboratory' called Demonstration and Experimentation Unit (UDEX) and afterwards in an ENEDIS rural network, within the SMAP project, where new technologies for the integration of RES in rural smart grids are assessed. INTRODUCTION The penetration of RES is expected to increase over the next decades. This potential rise is promoted in Europe by the European Initiative 20 20 20 [1] 1 and globally by the last United Nations Climate Change Conference in Paris (December, 2015) [2] 2 To fulfil their commitments, lot of countries have set targets and policies to stimulate the development and integration of renewable energy into the electrical system [3] Furthermore, the advancement in renewable energy technologies and engineering has boosted significantly the investment in clean energy, helping the deployment of RES [4] In 2015, renewable energy expanded significantly in terms of capacity installed and energy produced, with renewable energy 1 To reduce CO2 emissions by 20% to reduce primary energy use by 20% and to increase renewable energies by 20% 2 Primarily aimed at reducing global greenhouse gas emissions, setting a goal of limiting global warming to less than 2 degrees Celsius (degC) compared to pre industrial levels. investments in the power sector outpacing net investments in fossil fuel power plants [3] Furthermore, EV integration will be also an issue for the electric utilities. Whilst the integration of RES in the LV side of the network is causing overvoltages, the implementation of additional loads in the LV, such as EV, could cause voltage dips. As the European standard EN 50160 [5] defines the voltage requirements in distribution grids, and requires that the voltage stays within a band of /10% of the nominal voltage. The compliance with these statutory voltage limits would require a grid extension. A smart distribution transformer with OLTC can keep the voltage inside the statutory limits by changing automatically the tap of the transformer, avoiding or minimizing the need of a conventional grid reinforcement [6, 7] and allowing further integration of distributed RES and EV [8, 9] As functional testing of new solutions for voltage control is complicated in real networks, the research to assess the operation of the smart distribution transformer has been done in a new 'laboratory' UDEX, which consists in a real grid designed as a platform for the research of new products for the smart grids [10] Network operators require high reliability products with predictable behaviour to guarantee the correct operation of the grid. Afterwards, a smart transformer has been installed in an ENEDIS rural network, within the SMAP project, where new technologies for the integration of RES in rural smart grids are assessed. SMAP PROJECT SMAP is the first rural smart grid demonstrator project where smart grid solutions are tested to avoid or limit network reinforcement cost linked with photovoltaic (PV) deployment. This project targets to facilitate renewable energies in rural areas, and for develop and test innovative solutions, 24th International Conference on Electricity Distribution Glasgow, 12 15 June 2017