Motor differential protection 87M

Description

Overview

• The motor differential protection device adopts professional differential motor protection logic. It is an integrated protection and control unit developed for high- and low-voltage asynchronous motors, available for standalone panel installation or built-in mounting in switchgear cabinets.

Product Functions (ANSI)

• Differential Instantaneous Overcurrent (ANSI 87)
• Percentage Bias Differential Protection (ANSI 87M)
• Overcurrent Stage I (ANSI 50)
• Overcurrent Stage II (ANSI 51)
• Overcurrent Stage III (ANSI 51)
• Inverse Time Overcurrent (ANSI 51)
• Overload Protection (ANSI 49)
• Overload Protection (ANSI 49)
• Locked Rotor Protection (ANSI 48)
• Negative Sequence Overcurrent Stage I (ANSI 46)
• Negative Sequence Overcurrent Stage II (ANSI 46)
• Negative Sequence Inverse Time Overcurrent (ANSI 46)
• Zero Sequence Overcurrent (ANSI 50N / 51N)
• Thermal Overload Protection (ANSI 49)
• Long Start-up Time Protection (ANSI 48)
• Motor Start Blockin
• Overvoltage Protection (ANSI 59)
• Undervoltage Protection (ANSI 27)
• Zero Sequence Overvoltage (ANSI 59N)
• Overfrequency Protection (ANSI 81O)
• Underfrequency Protection (ANSI 81U)
• PT Circuit Break (ANSI 60)
• PT Voltage Loss (ANSI 60)
• Control Circuit Break
• System Power Loss
• Non-electrical Protection

Measurement and Control Functions

• Bus voltage: Ua, Ub, Uc, Uab, Ubc, Uca;
• Measured current: Ia, Ic;
• Power: Active power P, Reactive power Q, Power factor COSφ;
• Frequency: f;
• Electric energy: EP+, EP-, EQ+, EQ-;
• Supports 21 channels of active binary input (AC/DC 220V, DC 100V or DC 48V, shall be specified when ordering);
• Equipped with 11 protection output channels, 2 signal output channels, 1 closing position signal output channel, and 1 device power loss output channel.

Communication Functions

Communication Interfaces

• 1 Ethernet port
• 2 RS-485 ports, of which the second RS-485 port is multiplexed with the time synchronization port; communication and time synchronization are selected via configuration.

Communication Protocols

• Internal Ethernet 103 protocol or IEC 61850 protocol, MODBUS RTU protocol.

Time Synchronization

Supports time synchronization via communication messages, SNTP, and IRIG-B.

Setting Table

No.	Setting Name	Setting Range	Unit	Default Value	Remarks
1	Differential Starting Current Setting	0.1~100	A	1
2	Differential Instantaneous Overcurrent Setting	0.1~100	A	5
3	Inflection Point Setting	0.1~100	A	1
4	Percentage Bias Coefficient	0.1~0.9	—	0.5
5	Motor Rated Current	0.1~100	A	5
6	Motor Starting Time	0～600	S	5
7	Stage I Overcurrent Setting	0.1~100	A	8
8	Stage II Overcurrent Setting	0.1~100	A	7
9	Stage II Overcurrent Time Delay	0～100	S	0.5
10	Stage III Overcurrent Setting	0.1~100	A	5
11	Stage III Overcurrent Time Delay	0～100	S	1
12	Inverse Time Overcurrent Setting	0.1~100	A	5
13	Inverse Time Overcurrent Delay	0～100	S	1
14	Inverse Time Overcurrent Type	0~3	—	1	1=Normal, 2=Very, 3=Extreme
15	Overload Setting	0.1~100	A	5
16	Overload Time Delay	0～100	S	2
17	Overload Protection Type	0~2	—	1	0=Disabled, 1=Trip, 2=Alarm
18	Locked Rotor Protection Setting	0.1~100	A	2
19	Locked Rotor Protection Delay	0～100	S	1
20	Negative Sequence Stage I Overcurrent Setting	0.1~100	A	2
21	Negative Sequence Stage I Overcurrent Delay	0～100	S	1
22	Negative Sequence Stage II Overcurrent Setting	0.1~100	A	1
23	Negative Sequence Stage II Overcurrent Delay	0～100	S	2
24	Negative Sequence Stage II Protection Type	0~2	—	1	0=Disabled, 1=Trip, 2=Alarm
25	Zero Sequence Overcurrent Setting	0.1~100	A	2
26	Zero Sequence Overcurrent Time Delay	0～100	S	2
27	Zero Sequence Overcurrent Protection Type	0~2	—	1	0=Disabled, 1=Trip, 2=Alarm
28	Negative Sequence Current Thermal Coefficient	2~10	—	6	Default: 6
29	Thermal Time Constant	0.01~100	min	5
30	Heat Dissipation Time Constant	1~5	Times	5	Normally 1~5 times of thermal time constant
31	Overheating Alarm Level	10%~100%	—	80%
32	Long Starting Time Setting	0.1～100	A	5
33	Long Starting Time Enable Duration	0～100	S	3
34	Start Interval Time Setting	0～100	min	10
35	Undervoltage Block Starting Setting	1～400	V	70
36	Overvoltage Setting	1～600	V	120
37	Overvoltage Time Delay	0～100	S	0.5
38	Undervoltage Setting	1～400	V	80
39	Undervoltage Time Delay	0～100	S	1
40	Zero Sequence Overvoltage Setting	1～400	V	30
41	Zero Sequence Overvoltage Time Delay	0～100	S	0.5
42	Zero Sequence Overvoltage Protection Type	0~2	—	1	0=Disabled, 1=Trip, 2=Alarm
43	Overfrequency Setting	35～60	Hz	49
44	Overfrequency Time Delay	0～100	S	0.5
45	Underfrequency Protection Setting	35.0～65	Hz	51
46	Underfrequency Time Delay	0～100	S	0.5
47	Undervoltage Block Frequency Setting	1～400	V	20
48	Slip Block Frequency Setting	1～30	Hz/S	3
49	PT Circuit Break Time Delay	0～100	S	5
50	PT Voltage Loss Time Delay	0～100	S	5
51	Control Circuit Break Time Delay	0～100	S	10
52	System Power Loss Type	0~2	—	1	0=Disabled, 1=Trip, 2=Alarm
53	High Temperature Alarm Delay	0～100	S	0.1
54	High Temperature Trip Delay	0～100	S	0.1
55	Non-electrical Protection 1 Type	0～2	—	1	0=Disabled, 1=Trip, 2=Alarm
56	Non-electrical Protection 1 Time Delay	0～100	S	0.1
57	Non-electrical Protection 2 Type	0～2	—	1	0=Disabled, 1=Trip, 2=Alarm
58	Non-electrical Protection 2 Time Delay	0～100	S	0.1

Outline and Installation Dimensions

   

FAQ

Q：What types of motors require differential protection?

A:motor differential protection scheme

Motors of 2000 kW and above shall be equipped with differential protection. For motors below 2000 kW, differential protection is required if instantaneous current protection lacks sufficient sensitivity.

High-voltage motors for critical special applications (such as mine main drives and main ventilation) must be fitted with differential protection to ensure safe, reliable operation and avoid major losses and incidents.

Critical six-lead motors below 2000 kW shall also use differential protection as main protection for internal short circuits, when instantaneous protection cannot meet sensitivity requirements.

Q：What is the CT wiring configuration for motor differential protection?

For standard motors, the polarity end of CT (T/P marked terminal) must face the busbar or transformer side to ensure correct secondary current direction.

In motor differential protection CT connection, the wiring of differential protection of motor shall strictly follow A-A, B-B and C-C phase matching.

For units adopting motor differential protection self balancing, it is required to configure motor differential protection core balance CT and zero-sequence balance CT; please refer to the official wiring diagram for specific connection methods.