The Use of Emergency Components as Input Information Signals for Microprocessor Protection

A technique is proposed for the formation of emergency components of current and voltage of a power transmission line by a computational experiment in the MATLAB-Simulink dynamic simulating system (DSS) in order to use them as input information signals of additional stages of microprocessor protections with increased sensitivity. The emergency components of current and voltage are determined using orthogonal components. The emergency component of the short-circuit current is defined as the difference between the vectors (sinusoids) of the main harmonic of the short-circuit current and the current of the previous mode, if the effective value of this difference exceeds some predetermined value. Similarly, the emergency component of the voltage is determined, taking into account the fact that in emergency mode, the voltage at the place of installation of protection does not increase, but decreases. A computer software package (CSP) has been developed in the MATLAB-Simulink DSS to study the functional properties of microprocessor protection using emergency components of currents and phase voltages of a power transmission line of 6(10)–35 kV. The results of the formation of emergency components by models of digital measuring bodies of current and voltage protection are presented, confirming the operability of the developed software package. A CSP has been developed for calculating emergency components of currents and voltages of a power transmission line of 6(10)–35 kV using orthogonal components based on a mathematical model of the power supply unit of the protected line. The results of calculations of emergency components are presented, confirming the operability of the developed software package; a comparison of the results of calculating emergency components obtained by modeling in the MATLAB-Simulink DSS and using a CSP based on a mathematical model is also carried out.