CHAPTER 5: SETPOINTS S4 ELEMENTS
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL 5–81
• MINIMUM OPERATING CURRENT: Enter the minimum value of winding 1 phase A
current (in units of relay nominal current) required to allow the frequency decay
element to operate.
• MINIMUM OPERATING VOLTAGE: Enter the minimum value of voltage (in units of relay
nominal voltage) required to allow the underfrequency element to operate.
• FREQUENCY DECAY THRESHOLD: Enter the frequency (in Hz) below which the four
frequency rate of change levels of the frequency decay element will be allowed to
operate.
• FREQUENCY DECAY RATE 1(4): Enter the rate of frequency decay beyond which the
corresponding element operates.
FIGURE 5–31: Frequency decay scheme logic
MESSAGE
FREQUENCY DECAY
RATE 2: 1.0 Hz/s
Range: 0.1 to 5.0 Hz/s in steps of 0.1
MESSAGE
FREQUENCY DECAY
RATE 3: 2.0 Hz/s
Range: 0.1 to 5.0 Hz/s in steps of 0.1
MESSAGE
FREQUENCY DECAY
RATE 4: 4.0 Hz/s
Range: 0.1 to 5.0 Hz/s in steps of 0.1
MESSAGE
FREQUENCY DECAY
BLOCK: Disabled
Range: Logc Inpt 1 to 16, Virt Inpt 1 to
16, Output Rly 2 to 8, SelfTest
Rly, Vir Outpt 1 to 5, Disabled
To Next Page
Loading...
