Calculations > Protection > Protection for Enexis

The presence and settings of safeguards are checked with: Calculate | Security | Enexis | Tactics.

Security settings

Anomalous protection settings are detected first.

Safeguards in transformers, transport cables and descending distribution cables must be set according to the prescribed tactics. If a deviation is detected, the protection is reported, with the current setting and the prescribed setting.

What is tested?

•Fuse protection and first current protection in a transformer or transformer load

•First earth fault protection in a transport cable

•First current protection and first earth fault protection in a distribution cable

•First steam fuses/distribution fuses at either end of a transmission cable

Missing protections

Missing protections are reported second.

•A transformer must include a safeguard

•A transport cable or descending distribution cable must contain a fuse

A protection here is a fuse, current protection, differential protection or distancing protection.

Staffing

Thirdly, staffing faults in the distribution network are detected.

Relative to a sure protection, a preceding protection must be set at various currents with a larger time.

'Miscellaneous' currents run up to a maximum of 40 kA for symmetrical short-circuits and up to a maximum of 3000 A or 1000 A for single-phase short-circuits in an earthed or non-earthed network, respectively.

Fuses, current protections, distance protections and earth fault protections are considered.

If there is a deviation, the fuse and preceding fuse are reported.

Adjustability

Fourth, the adjustability of protective devices is tested.

In case of an error, the guard and its settings are reported, as well as the minimum and maximum adjustable values or the nearby adjustable values.

Intermediate protections

Fifth, intermediate protections are tested.

More than one sequential intermediate protection in a line is reported.

Last protections without I>>

Sixth, last first current protections without I>> are reported.

In such a case, this stage could be set.

Differential protections with different measuring transformers

Seventh, differential protections with anomalous measurement transformers are detected.

This concerns theInom of current measurement transformers.
A 7SD610 may have differentInom and never causes a report.

For an MBCI and a DL91, the primary sides must be the same.

For a DL4, the primary and secondary sides must be equal.

For a 7SD503, a 7SD74 and an RN25b, the primary sides must be equal in principle, but a discrepancy states that this is possible when using an intermediate current transformer.

Available but not set earth fault protections

Eighth, unset but available earth fault protections are reported.

These are non-set first earth fault protection, where the first current protection is set.

The also common check for cables with anInom greater than 1500 A and cables with a length less than 10 m are part of the general network check in Vision, to be carried out via Prepare.

Taktiek

Taktiek