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be between 1.2 × I s to 20 × I s , where I s is the current setting.
•
Calculate the theoretical operating time using the characteristic equations shown in Section
2.1.1. Check that the measured operating time is within IEC 60255-3 class 5.
6.5.1.6
DNOC element
The test circuit is shown in Figure 6.5.8.
V a
V b
Three-phase
voltage
source
V c
I a
A
Three-phase
I b
Current
A
source
I c
A
+
DC
power
−
supply
DC
voltmeter
DNOC element and their output signal number are listed below.
Measuring element
DNOC1F (FWD)
DNOC1R (REV)
The following shows the case when testing DNOC1F.
• Select "Logic circuit" on the Test screen to display the "Logic circuit" screen.
• Enter the signal number to be observed at monitoring jack as shown in Section 6.5.1.
• Apply three-phase balance voltage (=30V) and three-phase balance current.
Set I a to lag V a by DNC characteristic angle DNC θ . (The default setting of DNC θ is -45°.)
•
Changing the magnitude of three-phase balance current while retaining the phase angle with
the voltages, and measure the current I a at which the element operates. Check that the
measured current magnitude is within ± 5% of the current setting.
V
φ
Figure 6.5.8 Testing DNOC Element
Signal number
⎯
⎯
262
GRD150
TB1
-11
-12
-13
-14
-15
-16
Monitoring
jack
TB1
-1
-2
-3
-4
-5
-6
TB4
-18
-19
-20
(E)
140
156
6 F 2 S 0 8 4 2
A
0V
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