Excessive Operations Block; Successive Operations In A Certain Time Frame Block; Overvoltage, Undervoltage And Overcurrent Blocks; Quick Lowering Function - GE DTR GEK-106305A Instruction Manual

Digital tap changer controller

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2. OPERATION PRINCIPLES

Failed Tap-UP:

This state shows that the tap increase operation has failed. The DTR system changes to the Manual state,

independently of the state previous to the Tap-up attempt.

11. Successful Tap-Down:

This state shows that the tap decrease operation has been successful. The DTR system returns to the initial state,

previous to the tap decrease, either Manual or Automatic.

12. Failed Tap-Down:

This state shows that the tap decrease operation has failed. The DTR system changes to the Manual state,

independently of the state previous to the Tap-down attempt.

2.1.4 EXCESSIVE OPERATIONS BLOCK.

This function allows the user to limit the number of raising/lowering tap operations over the OLTC. The user can set

this function for maintenance purposes.

When the DTR is in automatic mode, and the maximum number of allowed operations is exceeded, it will change to

Manual mode. This function can be disabled by setting the Maximum number of operations to zero.

This function allows the user to limit the number of raising / lowering tap operations in a specified time interval.

When the regulator is in Automatic Mode and there are continuous operations at a higher speed than the one

specified by Number of Successive Operations and Time window settings, the DTR will change to Manual mode.

Once this function is enabled, it will disable itself after a certain time without operations over the OLTC.

This function can be disabled by setting the Number of Successive Operations to zero.

When the DTR is in automatic mode, before performing any operation over the OLTC, it checks that the voltage

levels are within the limits specified by Overvoltage and Undervoltage settings. It also checks that the measured

current is lower than Overcurrent setting. In order to enable control over different operations when in MANUAL

mode independently from the protection element blocks, the relay incorporates three settings: BLOQ. M. OVER_V,

BLOQ. M. UNDER_V y BLOQ. M. OVER_I, which allow to consider or not the block condition.

If the measured voltage exceeds the value set for Quick Lowering, Then the Operating Time becomes 0 s, and

therefore the lowering tap operation is instantaneous.

DTR Digital Tap Changer Controller

GE—106305A

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