Sir,
In a loss of field relay like EE make YCGF type (offset mho), the offset is taken as xd’/2 and circle diameter is as xd. How these parameters are arrived for setting? If a unit loses excitation, when the unit was working in full load, the load impedance will finally reach into the average values of direct and quadrature transient impedances. And if the units were at about 30% load, the load impedance will come to synchronous impedance average value. These values will be in –X direction as the current is reversed.
Only that much I know what I stated above. Please anybody explain how xd’/2 and xd are selected for the offset and diameter of offset mho relay used for loss of field protection
In a loss of field relay like EE make YCGF type (offset mho), the offset is taken as xd’/2 and circle diameter is as xd. How these parameters are arrived for setting? If a unit loses excitation, when the unit was working in full load, the load impedance will finally reach into the average values of direct and quadrature transient impedances. And if the units were at about 30% load, the load impedance will come to synchronous impedance average value. These values will be in –X direction as the current is reversed.
Only that much I know what I stated above. Please anybody explain how xd’/2 and xd are selected for the offset and diameter of offset mho relay used for loss of field protection