SEL-351/SEL-351A Protection System

The SEL-351 Protection System has built-in Ethernet and IEEE C37.118 synchrophasors, and is ideal for directional overcurrent applications. Optional MIRRORED BITS® communications and power quality monitoring add flexibility to solutions. The SEL-351 is the protection standard for utility and industrial electrical systems around the world.

16SEC	Access Security (Serial, Ethernet)
25	Synchronism Check
27	Undervoltage
32	Directional Power*
50BF	Breaker Failure Overcurrent
50G	Best Choice Ground
50N	Neutral Overcurrent
50	(P, G, Q) Overcurrent (Phase, Ground, Neg. Seq.)
50/51	Adaptive Overcurrent
51N	Neutral Time-Overcurrent
51	(P, G, Q) Time-Overcurrent (Phase, Ground, Neg. Seq.)
52PB	Trip/Close Pushbuttons*
59	Overvoltage
59	(P, G, Q) Overvoltage (Phase, Ground, Neg. Seq.)
67N	Directional Neutral Overcurrent
67	(P, G, Q) Directional Overcurrent (Phase; Ground, SEF*; Neg. Seq.)
79	Autoreclosing
81	(O, U, R) Frequency (Over, Under, Rate)
85	SEL MIRRORED BITS Communications*
DFR	Event Reports
HMI	Operator Interface
LGC	SELOGIC Control Equations
MET	High-Accuracy Metering
PMU	Synchrophasors
PQM	Voltage Sag, Swell, and Interruption*
SER	Sequential Events Recorder
BRM	Breaker Wear Monitor
HBL	Harmonic Blocking
LDE	Load Encroachment
LDP	Load Data Profiling*
LOC	Fault Locator
PPV	Phantom Phase Voltage
SBM	Station Battery Mon

* Optional

Front- and Rear-Panel Diagrams


Front		Rear

Complete Overcurrent Protection

Protect lines and equipment using phase, negative-sequence, residual-ground, and neutral-ground overcurrent elements with directional control.

Increased Overcurrent Element Security With Second-Harmonic Blocking

Use the second-harmonic blocking elements to detect transformer energization, and block selected tripping elements until inrush conditions subside.

Enhanced Breaker Monitoring

Inspect reports for the most recent trip and close operating times and average operating times, or gather trending data for up to 128 previous operations. This information allows timely and economical scheduling of breaker maintenance.

Fast Dropout Breaker Failure Element

Detect a failed circuit breaker with built-in breaker failure detection elements and logic.

Comparison

451

351

351A

751

751A

551/
551C

APPLICATIONS

Distribution Feeder Protection	•	•	•	•	•	•
Breaker Failure Protection	•	•	f	•	•	f
Generator Intertie Protection	•	•	•	+	+
Synchronism Check	•	•	•	+	+
Underfrequency Load Shedding	f	•	•	•	•
Undervoltage Load Shedding	f	•	•	•	+

PROTECTION

27/59 Under-/Overvoltage	•	•	•	•	+
32 Directional Power Elements	f	+		•	+
49 Thermal Overload	f
50 (P,N,G,Q) Overcurrent Element (Phase, Neutral, Ground, Neg. Seq.)	•	•	•	•	•	•
51 (P,N,G,Q) Time-Overcurrent Element (Phase, Neutral, Ground, Neg. Seq.)	•	•	•	•	•	•
67 (P,N,Q) Directional Overcurrent (Phase, Neutral, Neg. Seq.)	•	•	•	+
81 Over-/Underfrequency	•	•	•	•	•
Separate Neutral Overcurrent	•	•	•	•	•	•
Load-Encroachment Supervision	•	•	•	+
Mirrored Bits Communications	•	+		•	•
Sensitive Earth Fault Protection		+	+		+
Directional Sensitive Earth Fault Protection		+	+
Pilot Protection Logic	•	•
Rate-of-Change-of-Frequency (df/dt)	f	•	•	•	+
Harmonic Blocking	•	•	+
Arc Sense Technology (AST) High-Impedance Fault Detection	+			+
Arc-Flash Detection				+	+
Phantom Phase Voltage		•	•
Current/Voltage Channels	6/6	4/4	4/4	4/4	4/4	4/0
Complete Two-Breaker Control	•

INSTRUMENTATION AND CONTROL

79 Automatic Reclosing	•	•	•	+	+	•
Fault Locating	•	•	•	•
SELogic Control Equations With Remote Control Switches	•	•	•	•	•	•
SELogic Counters	•			•	•
Voltage Check on Closing	•	•	•	+	+
Operator Control Pushbuttons	•			•	•
SELogic Nonvolatile Latch	•	•	•	•	•	+
Nonvolatile Local Control Switches	•	•	+	•	•	•
Display Points	•	•	+	•	•	•
Multiple Settings Groups	•	•	•	•	•
Substation Battery Monitor	•	•	•	+	+
Breaker/Recloser Wear Monitor	•	•	•	•	•
Trip Coil Monitor	f	f	f	f	f	f
Voltage Sag, Swell, and Interruption (VSSI)	•	+
Load/Signal Profile Recorder	•	+		•	•
Sequential Events Recorder	•	•	•	•	•	•
Demand Meter	•	•	•	•	+	•
DNP3 Level 2 Outstation	+	•	•	+	+
Modbus Outstation		•	•	•	•	+
IEEE C37.118 Synchrophasors	•	•	•	•	•
Bay Control	•
Ethernet	+	•	•	+	+
IEC 61850	+	+	+	+	+
Simple Time Network Protocol (SNTP)	•	•	•	•	•
Independent Trip/Close Pushbuttons	+	+	+
Harmonic Metering		•	•
RMS Metering	•	•	•	•	•

•	Standard Feature
+	Model Option
f	This function may be created using settings

Project Description