Protection Relays ^{Version 3.1.2 : Feature Note-63 25/07/2001}

It is now possible to describe a protection relay's characteristic curve using any user defined equation. Please refer to the ERACS manuals for full information. To interact with the protection module the equation must include the following symbols: TS = Time multiplier setting or Time dial setting. M = Multiple of setting (I/Is). As an example, the IEC Standard Inverse characteristic would be defined using the following expression: TS * ( 0.14 / ( M^0.02 - 1 ) ) In addition to the standard arithmetic operators, +, -, *, /, the following functions are also available: ^ Power operator. ( ) Parentheses for grouping. Abs Returns the absolute value of its argument. Exp Returns the exponential of its argument. Ln Returns the natural log of its argument. Sqrt Returns the square root of its argument.