Investigation of the Influence of Non-Sinusoidal Voltage and Currents on Electricity Losses in a Power Transformer

In distribution networks, power transformers take the brunt of the influence of non-sinusoidal currents and voltages and can be a source of high losses in this situation and an element that causes imbalance in the metering system. It is known that one of the popular methods for searching for sources of increased losses is the balance method using an electric energy metering system.The paper studies the influence of higher harmonics on the value of losses in a power transformer, uses a balance method to assess the total losses of electricity during the operation of transformers in non-sinusoidal conditions and allows us to evaluate the process of the impact of non-sinusoidal currents and voltages on the operation of the transformer and the formation of loss values depending on typical combinations of values given harmonic components of currents.A model of a network section was built in the PSCAD simulation environment, which makes it possible to assess the losses of electricity in a power transformer for various forms of the voltage curve and the harmonic composition of the load currents. A series of experiments were carried out to simulate situations of non-sinusoidality of voltages and currents of loads, the values of no-load losses were determined for different levels of non-sinusoidal of voltages and currents of the load and various values of the phases of higher harmonics. Experimental studies of the influence of the frequency and initial phase of higher harmonics of load currents on the value of transformer losses were carried out.