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9692 Main transformer differential protection relay

9692 Main transformer differential protection relay

9692 main transformer differential protection relay is suitable for differential protection of high voltage side and low voltage side equipped with microcomputer backup protection, it constitutes a whole main transformer protection with 9681 main transformer high voltage backup protection relay, and 983 main transformer low voltage backup protection relay. The protection device is mainly used for the main transformer capacity of 10000KVA or more, and forms a complete protection of the main transformer with 984 main transformer backup operation box, 985 main transformer non electricity quantity protection devices.
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      The protection device is mainly used for differential protection of two winding main transformer, but if needed the three winding main transformer differential protection relay, you can choose the 9693 three winding main transformer differential protection relay of our company.

protection functions

      Differential current instantaneous trip protection

      Percentage differential protection (with second harmonic restraint, CT line-break locking)

      CT line-break alarm

      Y/△ turn on

      Non-electric protection

      slight gas protection – alarm

      severe gas protection- tripping operation

      Load slight gas protection-alarm

      Load  severe gas protection- tripping operation

      Pressure release (turn on- tripping operation; turn off- alarm)

      Temperature rise-alarm

      Over temperature- tripping operation

 

Functions of measurement and control

      High voltage current: IA、IB、IC;

      Low voltage current: Ia、Ib、Ic;

      Differential current: DIa、DIb、DIc;

 

Assistant functions:

      Fault recording

 

Communication mode

      485 communication

      Ethernet communication

      Fiber-optic communication

Protection Principle:

      Pilot differential current instantaneous trip protection

      Pilot differential current instantaneous trip protection is substantially reflected current difference on both sides of the transformer and makes quick action, to ensure to make quick action to get tripping operation, when the internal transformer has significant failure or external transformer on both sides between the CT happen short circuit.

Criterion of protective action: Icd>Isd

      Icd is the actual differential current between the two sides of the same phase between CT, and the Isd is the setting value of the differential current instantaneous trip protection

      Any one phase of the three phases satisfies Icd > Isd, differential protection means protector action exit jumps to all switches of main transformer.

      In actual operation differential current = Ih * cosφ1 + IL*KLjx*cosφ2  

      In that formula,  KLjx(low voltage side unbalance coefficient)= Ie2h(high voltage side twice rated current)/ Ie2l(low 

voltage side twice rated current)

      cosφ1 is the real angle of high voltage side;cosφ2 is the real angle of low voltage side. 

 
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209585994

209585994

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