Tension Sensor PFTL101A0.5KN

Tension Sensor PFTL101A0.5KN

Tension Sensor PFTL101A0.5KN

The settings for Full-scheme distance protection, mho characteristic function (ZMHPDIS) are done in primary values. The instrument transformer ratio that has been set for the analog input card is used to automatically convert the measured secondary input signals to primary values used in ZMHPDIS.

The following basics should be considered, depending on application, when doing the setting calculations:

• Errors introduced by current and voltage instrument transformers, particularly under transient conditions.

• Inaccuracies in the line zero-sequence impedance data, and their effect on the calculated value of the earth-return compensation factor.

• The effect of infeed between the IED and the fault location, including the influence of different Z0 /Z1 ratios of the various sources.

• The phase impedance of non transposed lines is not identical for all fault loops. The difference between the impedances for different phase-to-earth loops can be as large as 5-10% of the total line impedance.

• The effect of a load transfer between the terminals of the protected line, the fault resistance is considerable and the effect must be recognized.

• Zero-sequence mutual coupling from parallel lines.

The setting values of all parameters that belong to ZMHPDIS must correspond to the parameters of the protected line and be coordinated to the selectivity plan for the network.