Field

Field Description

Description

Device Description

Normal Inverse

α = 0.02 ; β = 0.14 (See below for details)

Very Inverse

α = 1.0 ; β = 13.5 (See below for details)

Extremely Inverse

α = 2.0 ; β = 80.0 (See below for details)

Long Inverse

α = 1.0 ; β = 120.0 (See below for details)

User Defined

Current (kA); Operating Time(s)

C.T. Ratio

C.T. Ratio. The C.T. Secondary is 5A hence for a 500/5 C.T. a ratio of 500:5 must be used.

Plug Setting

Determines the relay 'pick-up' current.

Time Multiplier

Alters the time of operation for a specific plug setting.

Definite Minimum Time

Definite Minimum Time of the Relay

C.T. Saturation

Multiple of the C.T's winding current.

Instantaneous Setting

Determines the current at which the relay operates instantaneously.

Instantaneous Time (ms)

Operating time for a fault current greater than the instantaneous setting.

Minimum Discrimination Time (ms)

The Minimum Discrimination Time for this relay

Max. Current Rating (kA)

Maximum fault (kA) clearance capability of the breaker.

•t(s) = Relay operating time in seconds

•k    = Time Multiplier

•I    =Actual Current Flowing

•I>   =Plug Setting * C.T. Ratio

•β,α = Curve Constants