ESO is testing a Lithuania-first voltage regulator

Posted by Karolis Mirinavičius

Energijos Skirstymo Operatorius (ESO), together with Innovation Centre established by Ignitis Group, are testing new voltage regulation technologies, which would allow to flexibly manage voltage in electricity distribution networks. The tested system automatically regulates voltage in each phase of electricity network separately by using voltage regulators. If necessary, the voltage in the network can be increased or decreased, thus ensuring a seamless operation of consumers’ devices. By performing the pilot project, the company is looking for the most innovative solutions world-wide to apply them in Lithuania.

It is important to maintain the electricity voltage in narrow ranges because in the event of its decrease – consumers’ devices can malfunction, and in the event of its increase – generation sources (powerplants of prosumers) connected to the network might disconnect. A standard voltage in the state’s networks is 230 V, with allowed deviation of ± 10%.

Voltage fluctuation in the network is unavoidable, which is made by uneven load of phases and a change in the load, but especially large network fluctuations occur more in remote locations, where ESO’s network capacity in most cases is limited. The fluctuations are worsen by the generation sources of the clients. In other words, the network is designed for consumption, and not generation.

A rapid decrease in voltage can be caused by connecting a large number of powerful devices, for example, in winter, when many start to use heat pumps and electric heaters. A similar situation can occur in a house, when several household appliances consuming a lot of power are turned on. Voltage fluctuations are best perceived by light bulbs – they flicker, dim or start to shine more brightly than usual.

If the network does not have a lot of capacity, and a prosumer is connected to it, there can be challenges of increasing voltage in the network. It is often experienced by prosumers themselves, when an increase in voltage in the network results in an increase in the internal network of the prosumer, which can activate the safety mechanism of a solar or wind farm and disconnect it.

Innovative solutions tested by ESO, allow to solve such problems in target locations. It improves the electricity quality for the consumers and, at the same time, allows for a delay in reconstruction of the entire part of the network.

Currently, a voltage regulator EcoVAR is being tested in a 2 km low voltage powerline near Baltoji Vokė, where there is on prosumer. A positive result was observed immediately after connecting the system – the voltage fluctuations in the network were reduced. The regulator will be tested until late autumn, in order to observe how it will manage the challenges created by a solar powerplant, especially in summer – the most intense solar generation period.

After the pilot project is concluded, the results of the project will be summarised and analysed. Decisions will also be made regarding the economic rationality of a national application of the respective technology. ESO has performed market consultations and is continuing to cooperate with the creators of the equipment and new technology, who would help solve the distribution network problems occurring due to rapidly growing distributed generation from renewables.

EcoVAR application in low voltage grid

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