8.14
SEL-734 Meter Instruction Manual Date Code 20090730
Logic
KYZ Outputs
The number of KYZ pulses is determined by user settings KEn, KEn_SCALE,
KE
n_UNITS, and can be calculated using Equation 8.1:
Equation 8.1
Any remainder left over after the KYZ-pulses calculation is carried over to the
next calculation.
KYZ energy data can be collected using two methods. The first uses a pickup
that records the rising edge of a pulse; the second records the rising and falling
edges. The KYZ outputs of the SEL-734 are designed for compatibility with a
pickup that records the rising and falling edge (see Figure 8.14). If using a
rising edge pickup, divide the required K
e
by two.
Figure 8.14 KYZ Pulse Pickup
The pulse width, KYZPWn, determines the minimum length of each output
pulse, and therefore, the maximum number of pulses per second. The possible
settings for KYZPWn are 25, 50, 75, and 100 ms according to your
specification.
If more pulses are generated in the second than can be pulsed in one second,
the remaining pulses are added to the queue of pulses for the following
second.
Table 8.5 KYZ Output Settings and Ranges
Setting Definition Range
EKYZ Enables KYZ elements N, 1–4
KEn_SCALE Determines output of KEn in Primary or
Secondary
PRI, SEC
KEn Pulse initiator output constant 0.0001–9999
KEn_UNIT Pulse output units UNITY, KILO, MEGA
KYZDn Energy value to be output Energy Quantities (see
Table 8.4)
KYZPWn Determines length of output pulse width 25, 50, 75, 100 ms
where:
K
e
=KEn • MF1 • MF2
where: MF1= CTR • PTR if KEn_SCALE = PRI
= 1 if KEn_SCALE = SEC
and
MF2 = 1 if KEn_UNITS = UNITY
= 0.001 if KEn_UNITS = KILO
= 0.000001 if KEn_UNITS = MEGA
t = time (typically 1 second)
R
previous
= Remainder from the previous calculation of the number of
KYZ pulses
Number of KYZ Pulses
Total Wh during t + R
previous
K
e
------------------------------------------------------------------------=
Courtesy of NationalSwitchgear.com
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