Schweitzer Engineering Laboratories SEL-311C - Relay Testing; Equipment Required

13.9
Date Code 20060320 Instruction Manual SEL-311C Relay
Testing and Troubleshooting
Relay Testing
Relay Testing
Use this section as a guide to test overcurrent, distance, and negative-sequence
directional elements in the SEL-311A, SEL-311B, and SEL-311C relays.
Note that the SEL-311A has two zones, the SEL-311B has three zones, and
the SEL-311C has four zones. Settings E21P, E21MG, and E21XG will need
to be set to “2” instead of “3” when testing the SEL-311A.
Equipment Required
The following equipment is necessary for initial checkout.
➤ Source of control power
➤ Source of three-phase voltages and at least two currents
➤ Ohmmeter or contact opening/closing sensing device
Checkout Procedure
Purpose: Be sure you received the relay in satisfactory condition.
Method:
Step 1. Inspect the instrument for physical damage such as dents or
rattles.
Purpose: Refer to the Relay Part Number and Hardware Identification Sticker
on the relay rear panel to verify the power supply voltage, dc control voltage,
and nominal ac signal magnitudes appropriate for the relay under test.
Method:
Step 1. Refer to the information sticker on the rear panel of the relay.
The Power options include 24 volts dc, 48 volts dc, and
250 volts ac/dc.
Step 2. Refer to the sticker attached to your relay to determine the
magnitude of voltage you should apply to the relay power
supply input terminals.
The voltage source should be capable of providing 12 watts
continuously at the rated voltage.
The Logic Input options include 24 volts dc, 48 volts dc,
110 volts dc, 125 volts dc, 220 volts dc, and 250 volts dc.
a. To assert a relay logic input, apply dc voltage to the
relay input terminals.
b. Refer to the sticker attached to your relay to determine
the magnitude of voltage you should apply to the relay
logic inputs.
Approximately four milliamps of current flow when
rated voltage is applied to a relay logic input.
The V/phase specification indicates the nominal ac
voltage that the relay is designed to measure. This
voltage is specified from line to neutral and assumes a
standard 4-wire wye ac voltage connection. This relay
is configured to accept 67 volts ac, line to neutral. The
relay measures other ac voltage magnitudes accurately,
as defined in Section 1: Introduction & Specifications.