Toshiba GR200 Series Instruction Manual page 344

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As shown in Figure 2.23-1, a single IED is located near Bus G. When a fault (F) occurs

on the line GH, the fault distance (GF) is calculated in percent using the following equation.

Fault information

Detailed information is displayed along with the distance to the fault (see Figure 2.23-2.c). The

output of the FL information is simplified by means of notations; these are summarized in

Table 2.23-2.

Table 2.23-2 Notation of fault information on screen

Outside boundary

No convergence†

†Note: The FL function can determine the convergence in the computation when the

difference between the maximum value and the minimum value is less than 0.2

km. For the convergence decision, the values are calculated three times: a value

calculated for the current samples, a value three samples prior to the current

samples and a value six samples prior to the current samples.

Setting and operation

To run the FL function, the user must provide several setting items: the direction for which

the fault location is required, the mode selection for impedance settings, the impedances† of

the local and adjacent lines, imbalance-impedances and compensation factors, distance-unit

for the FL function, and others.

†Note: For impedance settings, the user should convert the primary values to secondary

values with regard to the line VT and CT. Set impedances as total-impedances; do

not set impedances as impedance per distance-unit.

Impedance setting using symmetrical components

Provided the self-impedances and the mutual-impedances are symmetrically balanced (that is,

Distance to fault F

Fault distance (%) =

Length of Line GH

The FL function determines a fault location as being

outside of the boundary. The boundary is defined with

setting [FL_Line_km] or [FL_Line_mile].

If a number of computation results are scattered, the

FL function will select one of the resulting values from

where the scattering is minimal.

6F2S1915 (0.46)

GRZ200 (Soft 031 & 032)