The LJWD1-35 and LJWD1-35 current transformers are steel-tank oil-immersed devices designed for dual indoor and outdoor use in 50Hz power systems. They provide accurate current measurement, energy metering, and relay protection.

These transformers are capable of operating continuously under 120% of the rated current and are suitable for regions with altitudes not exceeding 4000 meters and ambient temperature variations ranging from -25°C to +40°C. Designed with oil-paper insulation and built for outdoor applications, they meet the requirements of 35kV power systems, offering reliable performance for energy metering, current measurement, and protection functions.

Type Designation for LJWD1-35 CT

Key Features and Structure of LJWD1-35 Current Transformer:

• L: Current transformer.
• J: Steel tank oil-immersed type.
• W: Outdoor type, also suitable for indoor installations.
• D: Indicates double secondary windings (absence of “D” indicates single secondary winding).
• 1: Design sequence code.
• 35: Rated voltage for 35kV systems.

This designation highlights the LJWD1-35 transformer’s durability, versatility, and support for single or double secondary windings in medium-voltage systems.

Construction of LJW(D)1-35 Current Transformers

The LJW(D)1-35 current transformer is a single-phase, oil-immersed, self-cooling type suitable for both indoor and outdoor installations. It features vacuum oil-filtering and vacuum oiling technology to enhance insulation and cooling efficiency.

The oil tank incorporates an air hole with a waterproof and snowproof cover, ensuring reduced oil oxidation by isolating the oil from external air. For 35kV-class systems, a diaphragm within the oil tank minimizes oil-air contact for improved longevity and stability. Thermal stability is enhanced by 75 times, and dynamic stability by 187.5 times compared to conventional designs.

Available models include single-ratio single-secondary, single-ratio double-secondary, double-ratio single-secondary, and double-ratio double-secondary configurations. Accuracy class options range from 0.2, 0.5, to 1.3(D), providing versatile solutions for measurement and continuous protection.

Technical Data for LJW1-35 and LJWD1-35 CT

• Rated insulation level: 40.5/95/1200kV.
• Rated secondary current: 5A.
• External insulation creepage distance: Standard ≥735mm; W2 type ≥1100mm.
• Refer to the table for rated primary current, accuracy class combinations, rated output, and dynamic/thermal stability current.

Type	Voltage Class (kV)	Rated Current Ratio (A)	COSΦ = 0.8 Measurement Class 0.2 Capacity (vA)	Capacity for Class 1 Continuous Protection	Weight (kg)
LJW1-11	11	5~400/5	10~15	Without continuous protection, without monitoring	21
LJW1-33	33	5~600/5	30~(50)	Without continuous protection, without monitoring	64
LJWD1-11	11	5~400/5	10~15	10~15	28
LJWD1-33	33	5~600/5	30~(50)	30~(50)	83

Notes: Custom LJW1-35 and LJWD1-35 current transformers can be manufactured to meet specific accuracy classes, primary current ratings, and output requirements for medium- and high-voltage systems.
For best performance, use only one specified primary current rating at a time to ensure accuracy and reliability.
Contact our team for tailored solutions designed for precise energy metering, current measurement, and reliable relay protection.

Outline and Dimensions of Installation

Ordering Guidelines and Special Requirements

• Type and current ratio of the transformer.
• Required accuracy class and secondary output specifications.
• Insulation level and specific service conditions, if applicable.
• Customization options for the oil-immersed external tank, including tailored dimensions, materials, and designs based on specific application requirements.

FAQs for LJWD1-35 and LJW1-35 Current Transformers

1. What are the primary applications of the LJWD1-35 and LJW1-35 Current Transformers?
   These transformers are used for current measurement, energy metering, and relay protection in 35kV power systems.
2. How does the oil-paper insulation enhance performance?
   Oil-paper insulation provides superior dielectric strength, improved thermal stability, and protection against environmental factors.
3. Can the LJWD1-35 and LJW1-35 transformers be customized?
   Yes, they can be tailored for specific accuracy classes, primary current ratings, output capacities, and insulation levels to meet unique operational needs.
4. What maintenance is required for these current transformers?
   Maintenance includes periodic oil quality inspections, cleaning of external surfaces, and ensuring the integrity of the oil-tank seals.
5. What environmental conditions are suitable for these transformers?
   They operate reliably at temperatures from -25°C to +40°C, altitudes up to 4000m, and in Class II pollution conditions.
6. Why choose LJWD1-35 and LJW1-35 transformers over resin-cast designs?
   Their robust oil-immersed construction offers better thermal stability and a higher tolerance for harsh environmental conditions, making them ideal for demanding outdoor applications.

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