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CHAPTER 5: SETTINGS FLEXLOGIC

D30 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL 5-181

[97] OR(3)

[98] TIMER 2

[99] = Virt Op 4

Now check that the selection of parameters produce the required logic by converting the set of parameters into a

logic diagram. The result is shown in the figure, which is compared to the logic for virtual output 4 diagram as a check.

Figure 5-92: FlexLogic equation for virtual output 4

7. Now write the complete FlexLogic expression required to implement the logic, making an effort to assemble the

equation in an order where Virtual Outputs that are used as inputs to operators are created before needed. In cases

where a lot of processing is required to perform logic, this can be difficult to achieve, but in most cases does not cause

problems as all logic is calculated at least four times per power frequency cycle. The possibility of a problem caused by

sequential processing emphasizes the necessity to test the performance of FlexLogic before it is placed in service.

In the following equation, virtual output 3 is used as an input to both latch 1 and timer 1 as arranged in the following

order:

DIG ELEM 2 OP

Cont Ip H1c On

NOT

AND(2)

= Virt Op 3

Virt Op 4 On

Virt Op 1 On

Virt Op 2 On

Virt Ip 1 On

DIG ELEM 1 PKP

XOR(2)

Virt Op 3 On

OR(4)

LATCH (S,R)

Virt Op 3 On

TIMER 1

Cont Ip H1c On

OR(3)

GE D30 User Manual

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