reactive power

The increasing penetration of renewable energy sources (RESs), such as photovoltaic and wind power plants, into the medium-voltage distribution grid creates significant concerns regarding voltage control at local substations. Understanding the specifics of the RES operation impact on the phenomenon and propagation of voltage fluctuations in the distribution grid is important for engineering solutions in the practice of RES design and operation. The presented article describes an algorithm for estimating the impact of RES on voltage fluctuations in the medium-voltage grid.

The widespread applying of electrical grids with voltage classes 330 and 750 kV with powerful units of nuclear and heat power plants creates a set of problems with normal modes ensuring in the Ukrainian energy system. Due to sufficiently great transverse capacitance of such overhead lines, significant amounts of reactive power excess are possible in the system. This phenomenon manifests itself especially in the load reduction hours in the power system through the visible voltage levels deviation at the energy-generating nodes in an upward direction.

The current state of the energy system of Ukraine is characterized by extensive use power lines with voltage classes of 330 and 750 kV. The charging power of such lines is quite significant, which generates significant amounts of reactive power in the network, which manifests itself especially in the hours of reducing the load in the power system with significant increases in voltage levels. Excess reactive power affect the modes of excitation regulators of synchronous generators narrowing their working range.

The use of extra-high voltage networks leads to a number of problems with compensation for excess reactive power. An option to avoid these problems is to apply asynchronized synchronous turbine generators, which have a number of advantages over traditional synchronous generators. These advantages are largely manifested under conditions of generator operation in power grids with excess reactive power. Typical examples of such power grids are power grid “Burshtyn Island” and “Power bridge “Ukraine–EU”.

Pumping stations that provide fluid transportation by pipeline are significant consumers of electricity. Energy overruns due to sub-optimal modes of operation of individual high-power units or sub-optimal number of simultaneously operating less powerful units are quite significant and can have a significant impact on overall energy consumption. Energy overruns at pumping stations also lead to significant overruns in electricity grid elements.

With the purpose of providing dynamic compensation of reactive power in power network, we offer the method of coordinated control for several power rectifiers of technological mechanisms of power supply systems.

It is proposed to include the principle of distributed generation of reactive power in the basic principles of constructing smart microgrids for non-commercial facilities. Individual reactive power compensation devices should be installed for its implementation at the points of final distribution of electricity networks of buildings and structures.