Date post: | 30-Dec-2015 |
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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 ConstructionCylinder 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 ConstructionCompensator:• 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
M
STZSetting
1
•Impedance measured by 3 phase unit
L
LL
I
VZr
3Setting
LLL
Z
VI
3
Relay Setting
Used to find required test current
•Impedance measured by 2 phase unit
L
LL
I
VZr
2 Setting
LLL Z
VI
2 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.