The MU2300 is a microprocessor-based numerical relay for voltage protection in electrical distribution networks. It provides multifunction voltage protection with low-set and high-set undervoltage and overvoltage stages with definite or inverse time characteristics. It can operate in single or three-phase configuration and includes features such as fault recording, output contacts, and Modbus RTU communication.

1. Introduction
The MU2300 is a microprocessor based
numerical relay for voltage protection
functions in electrical distribution network.
Features
• Multifunction numerical voltage
protection relay
• Low-set undervoltage stage (U<)
with definite-time or inverse-time
characteristic
• High-set undervoltage stage (U<<) with
definite-time
• Low-set overvoltage stage (U>)
with definite-time or inverse-time
characteristic
• High-set overvoltage stage (U>>) with
definite-time
• Negative sequence overvoltage
protection (U2>) with definite-time or
inverse-time characteristic
• Neutral displacement / residual
overvoltage protection (U0>)with definite-
time or inverse-time characteristic
• Can be used in single-phase or three-
phase operation
• Multi-function isolated digital input with
wide input voltage range
• Fault record and event code recording
• Five programmable voltage-free output
contacts
• Isolated RS485 Modbus - RTU
communication
Overvoltage&UndervoltageRelayMU2300
MU2300
Technical Data
INPUTS
Measuring input:
Rated voltage input : 57-130V
Rated frequency : 50 / 60 Hz
Rated auxiliary voltage:
Model MU2300-150D : 24~150V DC
Model MU2300-240AD : 85~265V AC
110~340V DC
Power consumption:
AC auxiliary voltage : 6 ~ 10VA typical
DC auxiliary voltage : 5 ~ 9W typical
Binary Input:
External binary input : 85~265V AC/DC
OUTPUTS
5 programmable contacts +1 IRF contact:
Rated voltage : 250V AC/DC
Continuous carry : 5 A
Make and carry for 0.2 s : 30 A
Contact specification:
Expected electrical life : 105 operations
Expected mechanical life : 5 x 106 operations
UNDER-VOLTAGE ELEMENT
Low set setting U< : 5 - 130V
High set setting U<< : 5 - 130V
Time multiplier,TMS : 0.5 - 100
Low set Definite time tU< : 0 - 600 s
High set Definite time tU<< : 0 - 600 s
OVER-VOLTAGE ELEMENT
Low set setting U> : 5 - 200V
High set setting U>> : 5 - 260V
Time multiplier,TMS : 0.5 - 100
Low set definite time tU> : 0 - 600 s
High set definite time tU>> : 0 - 600 s
COMMUNICATION
RS485 Modbus - RTU
ENVIRONMENTAL CONDITIONS
Temperature : -5˚C to +55˚C
Humidity : 56 days at 93% RH and
40˚C non-condensing
NEGATIVE SEQUENCE OVER-VOLTAGE
ELEMENT
Negative sequence over-voltage setting, U2>
: 5 - 200V
Time multiplier,TMS : 0.5 - 100
Negativesequenceover-voltagedefinitetimetU2>
: 0 - 600 s
RESIDUALOVER-VOLTAGEELEMENT
Residual over-voltage setting, U0> : 0.5 - 130V
Time multiplier,TMS : 0.5 - 100
Residual over-voltage definite time tU0> : 0 - 600 s

2. Overvoltage&UndervoltageRelayMU2300
11
1010
100100
00 0.10.1 0.20.2 0.30.3 0.40.4 0.50.5 0.60.6 0.70.7 0.80.8 0.90.9 11
TMS=1
TMS=5
TMS=3
TMS=10
TMS=8
Applied voltage/relay setting voltageApplied voltage/relay setting voltage
Operatingtime(sec)Operatingtime(sec)
UNDERVOLTAGE CHARACTERISTIC
0.01
0.1
1
10
100
0 2 4 6 8 10 12 14 16 18 20
TMS=1
TMS=8
TMS=10
TMS=5
TMS=3
Applied voltage/relay setting voltageApplied voltage/relay setting voltage
Operatingtime(sec)Operatingtime(sec)
OVERVOLTAGE CHARACTERISTIC
142 mm
165mm
Front
129 1 mm
1391mm
Panel Cutout
198 mm
34 mm
136mm
Side
TYPICAL APPLICATION DIAGRAMS
CASE DIMENSIONS
3
2
6
5
9
8
12
11
31
32
33
13
14
34
36
35
38
37
40
39
42
41
27
26
28
30
29
25
24
22
23
External
Digital
Input
Uaux
R1
R2
R3
R4
R5
A
B
C
Trip Contact
A
BC
Phase rotation
Internal
Relay
Failure
TerminationResistor
N-
P+
Communication
CableShield
Ordering Information
MU2300-150D For 50 / 60 Hz system, auxil-
iary voltage 24 ~ 150 V DC
MU2300-240AD For 50 / 60 Hz system,
auxiliary voltage 85 ~ 265 V
AC or 110~340 V DC
MODEL DESCRIPTION
3
2
6
5
9
8
12
11
31
32
33
13
14
34
36
35
38
37
40
39
42
41
27
26
28
30
29
25
24
22
23
External
Digital
Input
Uaux
R1
R2
R3
R4
R5
A
B
C
Trip Contact
A
BC
Phase rotation
Internal
Relay
Failure
TerminationResistor
N-
P+
Communication
CableShield
3
2
6
5
9
8
12
11
31
32
33
13
14
34
36
35
38
37
40
39
42
41
27
26
28
30
29
25
24
22
23
External
Digital
Input
Uaux
R1
R2
R3
R4
R5
A
B
C
Trip Contact
A
BC
Phase rotation
Internal
Relay
Failure
TerminationResistor
N-
P+
Communication
CableShield
3
2
6
5
9
8
12
11
31
32
33
13
14
34
36
35
38
37
40
39
42
41
27
26
28
30
29
25
24
22
23
External
Digital
Input
Uaux
R1
R2
R3
R4
R5
A
B
C
Trip Contact
A
BC
Phase rotation
Internal
Relay
Failure
TerminationResistor
N-
P+
Communication
CableShield
3Vp-p + Vresidual connection 2Vp-p + Vresidual connection
3Vp-n + Vresidual connection 3Vp-n connection