Schweitzer Engineering Laboratories SEL-787-2 Manual page 2

2
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 Table 1. For protection func-
tions specific to a given MOT, the relay is referred to as SEL-787-4X, SEL-787-3E, SEL-787-3S, SEL-787-2X,
SEL-787-21, or SEL-787-2E explicitly, where needed. Table 2 shows the protection features available across models.
Table 1 Current (ACI) and Voltage (AVI) Card Selection for SEL-787 Models
Model Description/Application
787-2X 2 Winding/Terminal Current Differential
787-21 2 Winding/Terminal Current Differential
1 Neutral Current Input
787-2E 2 Winding/Terminal Current Differential
1 Neutral Current Input
3 Voltage Inputs (Phase)
787-3E 3 Winding/Terminal Current Differential
1 Neutral Current Input
3 Voltage Inputs (Phase)
787-3S 3 Winding/Terminal Current Differential
3 Voltage Inputs (Phase)
1 Voltage Input (Vsync or Vbat)
787-4X 4 Winding/Terminal Current Differential
Table 2 SEL-787 Protection Elements (Sheet 1 of 2)
Protection Elements
87 Phase Differential
REF Restricted Earth Fault (REF)
50P Phase Overcurrent
50Q Neg.-Seq. Overcurrent
50G Ground Overcurrent
50N Neutral Overcurrent
51P Phase Time-Overcurrent
51Q Neg.-Seq. Time-Overcurrent
51G Ground Time-Overcurrent
51PC Combined Winding Phase
Time-Overcurrent
51GC Combined Winding Ground
Time-Overcurrent
SEL-787-2, -3, -4 Data Sheet
Slot Z Card
(MOT Digits)
6ACI
(81, 82, 85)
6ACI
(81, 82, 85)
6ACI
(81, 82, 85)
6 ACI
(81, 82, 85)
6 ACI
(81, 82, 85)
6 ACI
(81, 82, 85)
SEL-787-2X SEL-787-21
X X
a
X
X X
X X
X X
X
X X
X X
X X
Slot E Card
Slot Z Inputs
(MOT Digits)
IAW1, IBW1, ICW1,
IAW2, IBW2, ICW2
IAW1, IBW1, ICW1, 1ACI
IAW2, IBW2, ICW2 (A6, A7)
IAW1, IBW1, ICW1, 1ACI/3AVI
IAW2, IBW2, ICW2 (78, 79)
IAW1, IBW1, ICW1, 4 ACI/3 AVI
IAW2, IBW2, ICW2 (72, 73, 76, 77)
IAW1, IBW1, ICW1, 3 ACI/4 AVI
IAW2, IBW2, ICW2 (71, 75)
IAW1, IBW1, ICW1, 6 ACI
IAW2, IBW2, ICW2 (A1, A2, A5)
SEL-787-2E SEL-787-3E SEL-787-3S SEL-787-4X
X X
a a
X X
X X
X X
X X
X X
X X
X X
X X
X
X
Schweitzer Engineering Laboratories, Inc.
Slot E Inputs
IN
IN, VA, VB, VC
IAW3, IBW3,
ICW3, IN, VA,
VB, VC
IAW3, IBW3,
ICW3, VS/VBAT,
VA, VB, VC
IAW3, IBW3,
ICW3, IAW4,
IBW4, ICW4
X X
a a
X X
X X
X X
X X
X X
X X
X X
X X
X X