How to calculate the phase angle of relay protection
To calculate the phase angle involving multiple poles, the formula ϕ = −tan−1 (ω) − tan−1 (ω/10) is utilized. However, when a fault occurs and an arc is formed, the additional resistance from the arc alters the total impedance seen by protective relays. The value for forward load impedance is calculated in view of the full load of the transmission line with an addi-tional. Characteristic angle (in a directional protection equipment): angle between the polarisation quantity of relay and the normal to the tripping zone boundary line (see fig. Differential protection: zone protection which detects a fault by measuring and comparing currents at the input and output. Phase angle relays are essentially specialized control devices that regulate power flow in an electrical system.
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