Transcript KD Relay
KD Relay Application: • Compensator distance relay that provides a single zone of phase protection for all three phases. • It provides tripping for phase to phase, two phase to ground and three phase faults within the reach setting and sensitivity level of the relay KD Relay Construction Cylinder Unit: • Main function is to operate when the angle between two signal applied is within certain range. • Widely used as a directional unit and in impedance relays. KD Relay Construction Cylinder Unit: • T=KI1I2SIN(Ø12-Ø)-KS • Where K and Ø are design constants. • Different combinations of input quantities can be used for different applications, system voltages or currents or network voltages. KD Relay Construction Compensator: • Designated as T • Current to Voltage air gap transformer. • Voltage side has a tap which divides the winding in two sections. • The output voltage angle can be changed by connecting a resistor across one of the voltage winding sections KD Relay Construction Compensator: KD Relay KD Relay Operation: KD Relay KD Relay C3C Capacitor KD Relay Impedance Circle KD Relay Impedance Curve KD Relay KD RELAY Equations needed for testing Z Setting ST 1 M Relay Setting •Impedance measured by 3 phase unit Zr VLL 3 IL IL VLL 3 Z Setting Used to find required test current •Impedance measured by 2 phase unit Zr VLL 2 IL IL VLL 2 Z Setting Used to find required test current Tests Required • Main tests required are the compensator check, maximum torque angle and the impedance test for 3 phase unit and phase to phase units.