Woodward ESDR 4 Current Differential Protection Relay

mode until the terminal is de-energized.

If this input remains energized for at least 1 s, the faults detected in monitoring

level 2 are reset. This means that the relays will be de-energized and the text display

will be deleted from the screen as long as the monitored currents are not exceeding

the configured threshold level.

When this input is energized, the differential protection is disabled.This means that

the differential current is not monitored, no relay can be enabled and no text is dis

played.

This relay becomes enabled when the unit detects threshold limit 2 (main stage) has

been exceeded. The configured differential current characteristics and delay time will

determine how relay 1 functions.

This relay becomes enabled when the unit detects threshold limit 2 (main stage) has

been exceeded. The configured differential current characteristics and delay time will

determine how relay 2 functions.

This relay becomes enabled when the unit detects threshold limit 1 has been ex

ceeded. The configured differential current characteristics and delay time will deter

mine how relay 4 functions.

This relay is enabled when the unit is operational and the differential current is being

monitored. The relay becomes disabled if the monitoring is deactivated through any

of the following reasons:

• the internal self-monitoring has detected a malfunction of the unit. A correct func

tioning of the unit cannot be guaranteed and corrective action may be necessary.

• the set values for parameter "CT-ratio" or parameter "Generator Current" are out

side the permissible limits (see page 19).

• the digital input "Blocking" is energized.

• the parameter "Monitoring" is configured to "Off".

When in configuration mode (simultaneous pressing of "Digit↑" and "Cursor→"), the configuration screen can

be advanced by pressing the "Select" button. Should there be no entry, parameter change or other action for 60

seconds, the unit will automatically revert into Automatic mode.

During the configuration mode, the monitoring function is still active. This means inevitably, that while adjusting

parameters during operation, it is possible to cause a tripping of the relay.

adjust settings

[press "SELECT"]

Configuration mode "Select" button

Pressing the "Select" key activates the configuration mode, and the following pa

rameters can be enabled or changed within the given limits. Please you note that as

you advance through the configuration screens, by configuring some parameters as

"ON", additional screens must be configured relating to that parameter. If the pa

rameter is configured as "OFF", the additional screens will be disabled and not dis

played.

Software version

Software version

Displays the software version.

SPRACHE/LANGUAGE ----------------

Language selection english/german

The screens can be displayed in German or English.

curr. transform.

ratio     0000/x

CT-Ratio Selection 10 to 6.000/{x} A

The Ratio of the CTs being used is entered here. The CTs should be selected so that

in fault-free operation at generator rated current, at least 60 % of nominal current

flows in the CT-secondary. Failure to use properly a sized CT-Ratio leads to loss of

resolution and inaccuracies in the monitoring functions.

generator nomin.

current    0000A

Generator rated current 5 to 6.000 A

This value is used as reference value for the calculation and display of restraint cur

rent and differential current. The entered value of generator current must be at least

60% of the nominal current of the CT and must not exceed the entered value of  CT

nominal current.

Example CT-Ratio 500/5 A

Range of Generator rated current 300 A to 500 A.

If the nominal value is less than 50% of the transformer ratio, the message "Wrong

Entry" will be displayed on the screen in Automatic mode and the unit will de

activate monitoring functions (the Monitoring LED goes out).

automatic reset

relay       ON

Automatic reset of the relay ON/OFF

Applies only to monitoring level 2 (tripping).

Monitoring level 1 (warning) always Auto-resets.

ON................The relays de-energize automatically when the fault is no longer pre

sent. The screen input "Automatic reset of error text" determines

what happens to the Alarm-text in the display.

OFF..............The relays remain energized until they are reset.

monitoring

ON

Monitoring ON/OFF

ON................Monitoring of the differential current is active and the follow

ingscreens of this option are displayed.

OFF..............The monitoring is de-activated and the following screens are not dis

played.

release limit

Is/In     X=000%

Trigger Value IS/IN (X12) 50 to 300 %

Definition of the threshold characteristic for the monitoring of levels 1 and 2.

This value determines the horizontal position (X12-coordinates of points

P [X12/Y1] and P [X2/Y2]) of the corner points of the Warning and Tripping char

acteristics.

release limit

Id/In     Y=000%

Limit valueId

This value determines the vertical position (Y2-coordinate) of the corner point

P [X12/Y2] of the tripping characteristic (monitoring level2).