Protection Relays & Systems
1. What are the Core Functions of Protection Relays & Systems?
Abnormal Current Protection
The overcurrent relay detects line overload or short circuit by setting the threshold, triggering the circuit breaker to cut off the fault circuit (such as the MELPRO-D series supports high/ultra-high voltage distribution systems);
The ground fault direction relay can identify single-phase ground faults and locate the fault area, and is commonly used in distribution systems with neutral point grounding in the power grid;
The reverse power relay (such as the G2000 series) is dedicated to the protection of parallel generators to prevent equipment damage caused by reverse power.
Voltage Monitoring System
The PLR series three-phase voltage monitoring relay prevents the motor from starting when the voltage is abnormal through phase sequence detection and undervoltage threshold setting, avoiding overheating and damage to the winding;
The overvoltage/undervoltage relay dynamically adjusts the protection threshold to adapt to the 63-690V wide voltage range system and enhance equipment compatibility.
Ground Fault Detection
The SE-502 series uses 5mA high-sensitivity leakage detection technology, combined with internal neutral point grounding resistance to limit fault current to less than 100mA, meeting Class-A personal protection standards, and is suitable for portable generators and heating systems.
2. What are Protection Relays & Systems Used for?
Industrial Power System: In scenarios such as locomotive traction motors and high-voltage switching power supplies, instantaneous overloads and temperature fluctuations are dealt with by integrating differential relays and motor protection units;
Renewable Energy System: Cooperate with digital substation architecture (such as RTU remote terminal) to achieve distributed energy grid-connected protection, reduce 90% wiring costs, and shorten the commissioning cycle;
Agricultural Automation: The CP5 series single-phase current monitoring module is used for abnormal stagnation detection of irrigation system towers, and over-irrigation is avoided through an adjustable delay trigger mechanism.
3. Technology Evolution Trend of Protection Relays & Systems
Intelligent Upgrade: Dynamic adjustment of relay parameters is achieved through the PC configuration interface (such as the G0100 programming kit), supporting user-defined ranges and alarm thresholds;
Integrated Design: The use of bidirectional differential relays achieves dual protection of transformers while integrating thermal management technology to prevent thermal runaway of power devices;
Communication Protocol Compatibility: Compatible with international standards such as IEC 61850, realizing serial communication between protection relays and SCADA systems, and improving remote monitoring efficiency.