ASB-4401H Intelligent Transformer Protection Relays

Description

Overview of Transformer Protection Relays

• The ASB-4401H Digital Plant Service Transformer Protection, Measurement, and Control Unit belongs to transformer protection relays, suitable for high-voltage and low-voltage plant service transformers, and integrates protection, measurement, control, and communication functions.

Protection Functions (with ANSI Codes)

• Combined undervoltage and negative-sequence voltage startup overcurrent protection ANSI 51V
•  Zero-sequence voltage blocking high-voltage side zero-sequence overcurrent protection ANSI 50N/51N+59N
• Low-voltage side zero-sequence overcurrent protection ANSI 50N/51N
• Zero-sequence overvoltage protection ANSI 59N
•  Overload alarm ANSI 49
• Undervoltage protection ANSI 27
•  Overvoltage protection ANSI 59
• Transformer body protection functions: heavy gas trip, overtemperature trip, light gas alarm, overtemperature alarm ANSI 63, 49T
• PT wire break detection and busbar insulation monitoring ANSI 60
•  Control circuit break supervision No dedicated ANSI code

Communication Functions

• The device supports three communication modes: RS-485, CANbus, and Ethernet (to be specified at the time of ordering);
• The device uploads real-time data, including measurement data, waveform data, faults, alarm signals, and all protection settings, configurations, and coefficients; it supports remote online modification of settings and activation/deactivation of protection functions;

Event Logging and Fault Recording

Monitoring Functions

• This device measures analog parameters including current, voltage and frequency.
• It collects digital signals such as status of circuit breakers, energy storage devices, disconnectors and remote/local mode. Circuit breaker closing and opening controls are also available.

Setting Table

No.	Description	Setting Range	Upload & Download Conversion Factor
1	Control Word 1	0000～FFFF	×1
2	Control Word 2	0000～FFFF	×1
3	Control Word 3	0000～FFFF	×1
4	Stage 1 Time Delay (Stage 1 Overcurrent Protection Delay)	0.00～120.00s	×100
5	Stage 2 Time Delay (Stage 2 Overcurrent Protection Delay)	0.00～120.00s	×100
6	Stage 3 Time Delay (Stage 3 Overcurrent Protection Delay)	0.00～120.00s	×100
7	HV Side Stage 1 Zero-sequence Current Delay	0.00～120.00s	×100
8	HV Side Stage 2 Zero-sequence Current Delay	0.00～120.00s	×100
9	LV Side Stage 1 Zero-sequence Current Delay	0.00～120.00s	×100
10	LV Side Stage 2 Zero-sequence Current Delay	0.00～120.00s	×100
11	Zero-sequence Overvoltage Delay	0.00～120.00s	×100
12	Overload Delay	0.00～120.00s	×100
13	Undervoltage Delay	0.00～120.00s	×100
14	Stage 1 Overcurrent Setting (Instantaneous Overcurrent Setting)	0.40～99.99A / 0.10～20.00A	×100
15	Stage 2 Overcurrent Setting (Time-limit Instantaneous Overcurrent Setting)	0.40～99.99A / 0.10～20.00A	×100
16	Stage 3 Overcurrent Setting (Overcurrent Protection Setting)	0.40～99.99A / 0.10～20.00A	×100
17	Overload Current Setting	0.40～99.99A / 0.10～20.00A	×100
18	Spare Setting (Original Startup Setting)	—	×1
19	HV Side Stage 1 Zero-sequence Overcurrent Setting	0.02～5.00A	×100
20	HV Side Stage 2 Zero-sequence Overcurrent Setting	0.02～5.00A	×100
21	LV Side Stage 1 Zero-sequence Overcurrent Setting	0.02～5.00A (HV Auxiliary Transformer) 0.40～99.99A (LV Auxiliary Transformer)	×100
22	LV Side Stage 2 Zero-sequence Overcurrent Setting	0.02～5.00A (HV Auxiliary Transformer) 0.40～99.99A (LV Auxiliary Transformer)	×100
23	Zero-sequence Current Blocking Setting (for Zero-sequence Overvoltage)	0.10～99.99A	×100
24	Undervoltage Setting	5.00～100.00V	×100
25	Negative-sequence Voltage Setting	5.00～100.00V	×100
26	Zero-sequence Overvoltage Setting	1.00～120.00V	×100
27	Zero-sequence Voltage Blocking Setting (for Zero-sequence Overcurrent)	1.00～120.00V	×100
28	Undervoltage Blocking Setting (for Overcurrent Protection)	5.00～100.00V	×100
29	Overvoltage Delay	0.00～120.00s	×100
30	Overvoltage Setting	20.00～120.00V	×100
31~48	Reserved	—	—

Outline and Installation Dimensions

   

FAQ

Q：how to size up a current transformer for relay protection,Especially for transformer protection relays?

A:When selecting current transformers for relays used in transformer protection and transformer protection relay applications, it is necessary to comprehensively consider rated parameters, accuracy class, anti-saturation capability, secondary winding configuration and mounting method for protection in transformer and protective transformer scenarios; the higher the voltage level, the more stringent the technical requirements, ensuring reliable operation of the protection system.

Q：How does this device differ from transformer differential protection and transformer backup protection?

A:Transformer differential protection and backup protection are part of the main protection system for transformers, designed for medium- and large-sized transformers, whereas this device is primarily intended for smaller service transformers or other small transformers.

Q: Main protection functions?

A: Phase overcurrent, residual earth overcurrent, overload thermal protection, overvoltage & undervoltage.