Distance Elements Analysis - GE D90 Plus Instruction Manual

Line distance protection system

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CHAPTER 15: THEORY OF OPERATION

Distance elements analysis

LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL

negative-sequence currents in extra directional comparators. Both the currents are from

the protected line and are not affected by any compensation as the latter applies only to

the reach defining comparators: the mho, reactance, and blinder characteristics.

This subsection shows how to analyze the operation of the distance elements in steady

states using the results of short circuit studies. All quantities are secondary ohms, volts,

and amperes. Ground phase A and phase AB distance elements are analyzed. Assume the

following settings have been entered in the Settings > Protection > Elements > Group 1 >

Ground Distance menu.

Figure 467: Typical ground distance settings window

Assume the following signals are injected into the D90

Based on these signals and the programmed settings, the D90

From the assumed steady-state injection, the D90

DISTANCE ELEMENTS

calculates the following

also calculates the following.