Description
Overview of Zero sequence current protection relay
- ASP-523H Phase-to-Ground Short Circuit Intelligent Protection Device, also known as zero sequence current protection relay, is applicable to 400V TN power systems in power plants, coal mines, iron & steel plants, textile factories and other industrial sites.
- It effectively solves common faults such as transition resistance earth faults on MCC circuits, failure operation of molded case circuit breakers and thermal relays, which cause damaged equipment insulation, PC cascading tripping and large-scale power outages.
- By real-time monitoring zero-sequence CT current of each circuit, this device realizes early alarm prior to tripping and cuts off faulty power lines timely. It protects electrical equipment reliably and prevents cascading tripping and wide-range power blackouts to avoid severe economic losses.
Features of the System
- The ASP-523H phase-to-ground short circuit protection device monitors zero sequence currents and zero sequence fault currents. It realizes phase-to-ground short circuit (zero sequence) protection function when matched with open-type high-precision residual current transformer and circuit breaker shunt trip coil. Featuring compact structure and easy installation, the device supports communication networking through RS485 interface with stable and reliable operation performance
- It adopts zero phase sequence current sampling to accurately judge system insulation status, and trips rapidly to isolate faulty lines or motors. It prevents large-scale power outages caused by cascading tripping and helps on-site maintenance staff work out reasonable maintenance plans efficiently.
Technical Specifications
- Working Power Supply: AC/DC 85V—265V
- Alarm & Tripping Contact Capacity: 2500VA/300W
- Panel Display: Large-screen LCD, user-friendly interface, simple and intuitive operation
- Rated Voltage Level: 0.4kV, 0.69kV
- Phase-to-Ground Short Circuit Protection Setting: Primary current 0~1500A, matched with dedicated current transformer
- Zero-sequence Tripping Current: 0.05A~10A (adjustable)
- RMS Measuring Error: ±2%
- Tripping Time Delay: 0-99s
- Tripping Delay Error: ±25ms
- Data Transmission: RS485 bus, MODBUS-RTU communication protocol
- Installation Type: Embedded mounting
Main Functions
Protection Function
- Supports 4-level alarm setting values; tripping output can be enabled or disabled.
Communication Function
- Two communication modes available: Dual RS485 communication (please specify when placing orders).
-
Upload real-time data including measured values, fault signals, alarm signals, all protection settings, configurations and coefficients. Remote online setting modification and protection function switching are supported.
-
Receive control commands from upper system, including system time synchronization, parameter setting, data reading and writing commands.
Operation Cabinet Function
- The closing and opening current inside the device features self-adaptation.
Self-check Function
- Automatically detect faults of RAM, ROM, A/D module and power loss.
-
Automatically verify parameters such as setting values, configurations and coefficients.
Event Recording & Fault Wave Recording
- Record protection operation events and device self-check faults.
-
Record type, occurrence time and operating parameters during protection actions; record type and occurrence time of device self-check faults.
Monitoring Function
- Remote measurement function for analog quantities such as current and frequency.
-
Remote control function for circuit breaker closing, opening and energy storage.
Display Function
- Equipped with Chinese LCD display, status indicators and operation keys on the panel. It realizes real-time monitoring, online setting adjustment and protection function switching. Fault indicators can be reset via local reset key or remote control.
Outline and Installation Dimensions
FAQ
Q：what is positive negative and zero sequence current?
A:As core parameters for ground fault zero sequence current and zero sequence current relay, positive-sequence current is the symmetrical three-phase operating component with phase sequence A→B→C under normal working conditions. Negative-sequence current refers to symmetrical three-phase unbalanced component with reverse phase sequence A→C→B. Zero-sequence current means three-phase currents with identical phase and magnitude, which can only flow through grounding paths and represents earth fault signals. They respectively reflect normal system operation, asymmetric faults and earth faults of power systems.
Q：what is a zero sequence current transformer?
A:It is a special current transformer used to detect zero-sequence current for earth fault protection.
Q：In which relay protection products is zero-sequence current protection applied?
A:Zero-sequence current protection is a common relay protection function, widely adopted in line protection, transformer protection, motor protection and other related devices.
Reviews
There are no reviews yet.