Date Code 20001006 Installation 2-13
SEL-351 Instruction Manual
Refer to the serial number sticker on the relay rear panel for the nominal current ratings (5 A or
1 A) for the phase (IA, IB, IC) and neutral (IN) current inputs (listed under label: AMPS AC).
The neutral (IN) current input also has a 0.05 A nominal current option.
Models 0351x0 and 0351x1
Note the polarity dots above terminals Z01, Z03, Z05, and Z07. Refer to Figure 2.7 through
Figure 2.14 for typical ct wiring examples.
Refer to the serial number sticker on the relay rear panel for the nominal current ratings (5 A or
1 A) for the phase (IA, IB, IC) and neutral (IN) current inputs (listed under label: AMPS AC).
The neutral (IN) current input also has a 0.05 A nominal current option.
Potential Transformer Inputs
Models 0351xT and 0351xY
The pt wiring harness includes a prewired 6-position connector. Plug the connector into terminals
Z09 through Z14. The connector is keyed uniquely and locks in place upon insertion.
Note the signal labels (VA, VB, VC, N, VS, NS) on terminals Z09 through Z14. Figures 1.2 and
1.3 show the internal connection (wye or delta) for terminals VA, VB, VC, and N. Note also that
VS/NS is a separate single-phase voltage input.
Wye-Connected Voltages
Any of the single-phase voltage inputs (i.e., VA-N, VB-N, VC-N, or VS-NS) can be connected to
voltages up to 150 V (or 300 V; see Table 1.2) continuous. Figure 2.7 and Figure 2.9 through
Figure 2.12 show examples of wye-connected voltages. Frequency is determined from the voltages
connected to terminals VA-N and VS-NS (see subsections Synchronism Check Elements and
Frequency Elements in Section 3: Overcurrent, Voltage, Synchronism Check, Frequency, and
Power Elements).
Models 0351xT and 0351xY part numbers with a numeral “2” or “5” in the field underlined below
(sample part numbers) indicate wye-connected voltage inputs:
0351xT425331411 0351xYH42542X1
0351xT455331411 0351xYH45542X1
Delta-Connected Voltages
Phase-to-phase voltage (up to 300 V continuous) can be connected to voltage inputs VA-VB, VB-
VC, or VC-VA. Figure 2.8 shows an example of open-delta connected potential transformers
connected to voltage inputs VA, VB, and VC. No connections are made to terminal N. Frequency
is determined from the voltages connected to terminals VA-VB and VS-NS (see subsections
Synchronism Check Elements and Frequency Elements in Section 3: Overcurrent, Voltage,
Synchronism Check, Frequency, and Power Elements).
Courtesy of NationalSwitchgear.com
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