Modelling of Dynamic Compensation for Isolated Neutral Power Network

Abstract

The paper deal with causes and consequences of the negative influence of harmonic components of currents and voltages in medium voltage distribution networks. The dynamic compensation benefits for filtering harmonic components of currents and voltages and eliminating current and voltage distortion from the power system are considered. In the paper the model of isolated neutral power network with the dynamic compensation device is created by simulation in the Matlab Simulink software. In the model a three-phase network was simulated by blocks from the SimPowerSystem database and the non-sinusoidal load was simulated by a three-phase bridge diode rectifier. The dynamic compensation filtering device is simulated by an inverter on IGBT-transistors and consisted of shunt reverse diodes, smoothing filters and capacitive storage. The simulation results show the reduction of the voltage distortion limits to the normalized values, thus we can eliminate the non-sinusoidal form of the voltage curve and make it sinusoidal by dynamic compensation in the distribution network. The dynamic compensation device operates correctly in the created model and is suitable for high-nonlinear, inductive, fast-changing and harmonic-generating loads, as it effectively fights against the violation of the quality of electrical energy.

Modeling of operating modes of relay protection in electrical networks with insulated neutral

“…Thus, the current inputs to which the residual current transformers are connected will not be queried. If it becomes necessary to put these lines into operation, the corresponding current channels can be queried in the terminal settings [12].…”

“…Protection is performed with definite time delay. At zero value of the setpoint, the minimum response time of the protection is 40 ms [11,12].…”