Schweitzer Engineering Laboratories, Inc.
SEL-787-3, -4 Data Sheet
Major Features and Benefits
The SEL-787 Transformer Protection Relay provides unsurpassed protection, integration, and control features in a
flexible, compact, and cost-effective package. The SEL-787 offers an extensive variety of protection features, depending
on the model and options selected. In this document, SEL-787 refers to all the models in
. For protection func-
tions specific to a given MOT, the relay is referred to as SEL-787-4X, SEL-787-3E, or SEL-787-3S explicitly, where
needed. Model options SEL-787-4X, SEL-787-3E, and SEL-787-3S are all considered base models.
shows the
protection features available across different models.
SEL-787-3E Model
SEL-787-3S Model
SEL-787-4X Model
Table 1
Current (ACI) and Voltage (AVI) Card Selection for SEL-787 Models
Model
Description/Application
Slot Z Card
(MOT Digits)
Slot Z Inputs
Slot E Card
(MOT Digits)
Slot E Inputs
787-4X
4 Winding/Terminal Current Differential
6 ACI
(81, 82, 85)
IAW1, IBW1, ICW1,
IAW2, IBW2, ICW2
6 ACI
(A1, A2, A5)
IAW3, IBW3, ICW3,
IAW4, IBW4, ICW4
787-3E
3 Winding/Terminal Current Differential
1 Neutral Current Input
3 Voltage Inputs (Phase)
6 ACI
(81, 82, 85)
IAW1, IBW1, ICW1,
IAW2, IBW2, ICW2
4 ACI/3 AVI
(72, 73, 76, 77)
IAW3, IBW3, ICW3,
IN, VA, VB, VC
787-3S
3 Winding/Terminal Current Differential
3 Voltage Inputs (Phase)
1 Voltage Input (Vsync or Vbat)
6 ACI
(81, 82, 85)
IAW1, IBW1, ICW1,
IAW2, IBW2, ICW2
3 ACI/4 AVI
(71, 75)
IAW3, IBW3, ICW3,
VS/VBAT, VA, VB,
VC
SEL-787-3, -4 Transformer Protection
Relay
