Product Overview
The LDR Series is a new generation of relay protection equipment developed for power plants, substations, distribution stations and switchgear systems. It provides comprehensive protection for primary equipment such as overhead lines, cable feeders, transformers, motors and capacitor banks at voltage levels of 35kV and below.
The device adopts a highly integrated microcomputer platform, high-precision current and voltage transformers, high-insulation intermediate relays and reliable switching power supply modules. Its compact structure, complete protection configuration, strong anti-interference capability and low power consumption make it suitable for direct and decentralized installation in switch cabinets.
Key Features
- Designed for relay protection in power plants, substations and distribution stations.
- Suitable for overhead lines, cable lines, transformers, motors and capacitor protection.
- Applicable to electrical systems at 35kV and below.
- High integration with a compact structure for switch cabinet installation.
- High-precision current and voltage measurement for reliable protection operation.
- Strong anti-interference capability for harsh electrical environments.
- Low power consumption design for continuous operation.
- Available in multiple LDR Series structures, including panel and compact cabinet formats.
Main Technical Parameters
|
Item |
Specification |
|
Rated frequency |
50Hz |
|
AC voltage |
100V, circuit voltage or VV wiring |
|
Open circuit |
DC 24V, 5mA, provided internally by the device |
|
Open contact capacity |
Can continuously connect DC220V, 5A current under pure resistive load |
|
Power consumption |
DC circuit <=5W; AC circuit <=0.5VA |
|
Protection action time |
Inherent protection action time <=35ms at 1.5 times the set value |
|
Phase current measurement range |
0.1In to 20In |
|
Zero sequence current range |
0.1A to 6.25A |
|
Voltage measurement range |
5V to 150V |
Conditions of Use
|
Condition |
Specification |
|
Relative humidity |
45% to 90% |
|
Atmospheric pressure |
80kPa to 110kPa |
|
Operating temperature influence |
Within -10°C to +55°C, operating value variation due to temperature change is not more than +/-1% |
|
Installation environment |
Suitable for direct or decentralized installation on switch cabinets |
Appearance and Installation Dimensions
|
Model |
Reference Dimensions |
|
LDR-310H/V |
Front width 156 mm; front height 75 mm; body depth 96 mm; installation cutout approx. 148 x 70 mm |
|
LDR-610 |
Front size approx. 135 x 175 mm; depth approx. 80 mm; rear width 121 mm; installation cutout approx. 123 x 154 mm |
|
LDR-6500 series style |
Large panel type with color display and front operation keys for cabinet-mounted relay protection |
Typical Applications
- Power plant auxiliary power systems
- Substation feeder protection
- Distribution station switchgear cabinets
- Overhead line and cable line protection
- Transformer, motor and capacitor protection
- Photovoltaic, energy storage, electrical grid and industrial power projects
- 35kV and below medium-voltage distribution systems
Why Choose This Product
The LDR Series combines reliable protection logic, high-precision measurement and cabinet-friendly installation in one device. It helps reduce separate protection components, improves operation visibility, and supports stable protection performance in demanding medium-voltage distribution environments.
Ordering Information
When ordering, please confirm the application object, system voltage, rated frequency, current transformer ratio, voltage input method, protection function requirement, installation model, communication or alarm requirements, and cabinet mounting dimensions.
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