Digital Multifunction Protective Relay ASL-591H

Description

Overview of Digital Multifunction Protective Relay

• The ASL-591H Microprocessor-Based Comprehensive Protection Device, a digital multifunction protective relay, is suitable for the comprehensive protection of 10 kV and below incoming and outgoing lines in ring main units and gas-insulated switchgear, as well as 380 V low-voltage incoming and outgoing lines in distribution rooms.

Features of Numerical Protection Relay

• This multifunction protection relay is suitable for plant service transformers, power supply feeders and bus tie protection at 10 kV and below. It supports AC/DC 220 V and DC 110 V power supplies (24 V/48 V available on request). Featuring a compact design, it is easy for instrument room installation.

Functions of Digital Multifunction Protection Relays

• Two-stage overcurrent protection (instantaneous current tripping & definite-time overcurrent), each stage can be independently enabled or disabled;
• Overload protection: output configurable for tripping or alarm;
• Zero-sequence overcurrent protection: output configurable for tripping or alarm;
• Inverse-time overcurrent protection: fixed output for tripping;
• Non-electrical protection: heavy gas tripping (transformer door interlock), over-temperature tripping, light gas alarm, over-temperature alarm, etc.

Event Logging Function of Digital Multifunction Protection Relay

• The log records events including protection trip events, alarm events, and device self-test failures;
• It records the type and time of protection trip events, as well as the type and time of device self-test failures.

Numerical Protective Relays – Communication Functions

• Upload real-time data, including measurement data, fault alarm signals, and protection settings.
• Receive control commands from higher-level systems.

Communication Interface

• This device provides a high-speed, reliable RS-485 interface for external communication. It supports the standard MODBUS protocol.

Rated DC Specifications

• Voltage: 220 V, 110 V;
  DC voltage ripple factor: ≤2%; voltage fluctuation: 80–115% of rated voltage

Rated AC Specifications

• Rated AC current In: 5 A, 1 A;
• The AC power waveform is sinusoidal, with a distortion factor not exceeding 2%;
• Frequency fn: 50 Hz (60 Hz option available; specify when ordering), with a tolerance of ±0.5%.

Dimensions of Numerical Protection Relays

Multifunctional Protection Relay Setting Sheet

No.	Name	Range	Step	Remarks
1	Stage 1 Protection Setting (Instantaneous Current Trip)
1.1	Stage 1 Protection Enable	1/0	—	Stage 1 protection: Enable(1) / Disable(0)
1.2	Stage 1 Time Delay	0~120.00s	0.01s
1.3	Stage 1 Setting Value	0.40~99.99A	0.01A
2	Stage 2 Protection Setting (Definite-time Overcurrent)
2.1	Stage 2 Protection Enable	1/0	—	Stage 2 protection: Enable(1) / Disable(0)
2.2	Stage 2 Time Delay	0~120.00s	0.01s
2.3	Stage 2 Setting Value	0.40~99.99A	0.01A
3	Overload Setting
3.1	Overload Protection Enable	1/0	—	Overload protection: Enable(1) / Disable(0)
3.2	Overload Trip Mode	1/0	—	Overload: Trip(1) / Alarm(0)
3.3	Overload Time T	0~120.00s	0.01s
3.4	Overload Current I	0.40~99.99A	0.01A
4	Zero-sequence Overcurrent Setting
4.1	Zero-sequence Overcurrent Enable	1/0	—	Zero-sequence overcurrent protection: Enable(1) / Disable(0)
4.2	Zero-sequence Overcurrent Trip Mode	1/0	—	Zero-sequence overcurrent: Trip(1) / Alarm(0)
4.3	Zero-sequence Time Delay	0~120.00s	0.01s
4.4	Zero-sequence Setting Value	0.5~99.99A	0.01A
5	Inverse-time Overcurrent Setting
5.1	Inverse-time Overcurrent Enable	1/0	—	Inverse-time overcurrent protection: Enable(1) / Disable(0)
5.2	Inverse-time Time Constant T	0.1~120.00s	0.01s	Time constant of inverse-time overcurrent protection
5.3	Inverse-time Current Setting I	1~10A	0.01A	Setting value of inverse-time overcurrent protection
6	Non-electrical Protection Setting
6.1	Non-electrical Protection 1 Enable	1/0	—	Non-electrical protection 1: Enable(1) / Disable(0)
6.2	Non-electrical Protection 1 Trip Mode	1/0	—	Non-electrical protection 1: Trip(1) / Alarm(0)
6.3	Non-electrical Protection 2 Enable	1/0	—	Non-electrical protection 2: Enable(1) / Disable(0)
6.4	Non-electrical Protection 2 Trip Mode	1/0	—	Non-electrical protection 2: Trip(1) / Alarm(0)
6.5	Non-electrical Protection 3 Enable	1/0	—	Non-electrical protection 3: Enable(1) / Disable(0)
6.6	Non-electrical Protection 3 Trip Mode	1/0	—	Non-electrical protection 3: Trip(1) / Alarm(0)
6.7	Non-electrical Protection 4 Enable	1/0	—	Non-electrical protection 4: Enable(1) / Disable(0)
6.8	Non-electrical Protection 4 Trip Mode	1/0	—	Non-electrical protection 4: Trip(1) / Alarm(0)
6.9	Non-electrical 1 Time Delay	0.1~120.00s	0.01s
6.10	Non-electrical 2 Time Delay	0.1~120.00s	0.01s
6.11	Non-electrical 3 Time Delay	0.1~120.00s	0.01s
6.12	Non-electrical 4 Time Delay	0.1~120.00s	0.01s
6.13	Non-electrical Parameter Value	0000～FFFF	—
7	General Setting
7.1	Three-element Wiring Enable	1/0	—	Three-element wiring: Enable(1) / Disable(0)
7.2	Current Transformation Ratio	0～9999	1

FAQ

Q：How are comprehensive protection relays typically installed and used, and what types of equipment can they protect?

A:Compact comprehensive protection devices are suitable for installation in ring main units and high-voltage switchgear. With control in numerical protection relay integrated, they provide complete protection for feeders, feeder terminals, distribution transformers and small motors.

Q What is this relay?

A microprocessor-based IED integrating protection, measurement, control, fault recording and communication, replacing multiple discrete electromagnetic relays for power system protection.

Q Core advantages vs traditional relays

All-in-one compact design, high precision settings, built-in fault waveform recording, remote communication, continuous self-diagnosis and no mechanical drift.

Q Common built-in protection elements

50/51 overcurrent, 50N/51N earth fault, 67 directional overcurrent, 27/59 undervoltage/overvoltage, 46 negative sequence, 32 reverse power, 87 differential, 81 frequency protection, breaker failure & trip circuit supervision.

Q Typical application objects

10/35kV feeders, distribution transformers, medium-voltage motors, capacitor banks, bus tie & incoming cabinet auto transfer logic.

Q Required input signals

Three-phase CT current, three-phase PT voltage, zero-sequence current; digital inputs for breaker status & interlock signals, digital outputs for trip, close and alarm.

Q Built-in circuit monitoring

Supports PT fuse failure and CT broken wire detection, automatically alarms and blocks relevant protection to prevent false tripping.

Q Ways to configure parameters

Local panel operation, PC software via USB/485, or remote download through SCADA system.

Q Protection coordination principle

Adopt definite/inverse time curves with time & current grading to ensure selective tripping between upstream and downstream equipment.

Q Supported protocols

Modbus, IEC 103/104, DNP3, IEC 61850 with GOOSE for smart substation interlocking.

Q Key data recording

Real-time electrical measurements, event logs, fault oscillography and action records for post-fault analysis.

Q False tripping main causes

CT polarity/ratio error, PT abnormality, over-sensitive settings, electromagnetic interference or unremoved blocking signals.

Q Protection fails to trip

Loss of control power, CT secondary open/short circuit, excessively high pickup values, broken trip circuit or external interlock locking.

Q Self-check alarm

Hardware failure of power supply, mainboard or memory; replace the unit or send for factory repair.

Q Necessary commissioning items

CT/PT polarity check, secondary injection test, DI/DO loop verification, communication debugging and setting file backup.

Q Routine maintenance

Monthly status check; annual terminal tightening and dust cleaning; full function inspection during major overhaul every 4~6 years.

Q Optional extra features

Auto-reclosing, cold load pickup, password permission lock for parameter modification, IEC 61850 GOOSE peer-to-peer intertrip.

Q Usage value

Reduces cabinet space, wiring workload and fault points, widely adopted in new distribution substations and industrial power distribution systems.