Overview
The LCWD1-35 (LABN1-35W2) 35kV outdoor oil-immersed current transformers are precision electromagnetic instruments designed for accurate current measurement, energy metering, and relay protection in 35 kV class AC power systems. Operating at 50 Hz or 60 Hz, these transformers use electromagnetic induction to deliver galvanically isolated secondary current signals proportional to the primary current.
These compact, oil-immersed CTs feature robust porcelain bushings and a sealed oil-filled design for reliable outdoor performance under harsh environmental conditions, ensuring long-term stability and insulation integrity.
Key Ratings Snapshot
| Item | Specification |
|---|---|
| System voltage class | 35 kV class |
| Rated frequency | 50 Hz / 60 Hz |
| Rated secondary current | 5 A |
| Accuracy classes | 0.2S, 0.5, 10P15, 10P20 |
| Rated burden | 0.2S: 30 VA, 0.5: 50 VA, 10P20: 50 VA |
| Burden power factor | cos phi = 0.8 (lagging) |
| Insulation level | 40.5/95/185 kV (Um/Up/Ud) |
| Creepage distance | Standard: >=735 mm; W2: >=1100 mm |
| Pollution class | Class II or Class III |
| Structural variants | LCWD1-35, LABN1-35W2 |
Construction
The LCWD1-35 series features oil-immersed construction with porcelain bushing insulation, providing superior dielectric strength, moisture resistance, and weatherability for outdoor service. The core assembly undergoes vacuum drying and is filled with insulating oil to ensure high insulation performance and thermal stability over decades of operation.
A top-mounted oil conservator includes oil level and temperature indicators for easy maintenance monitoring. The metallic base provides secure mounting, while the porcelain housing offers robust mechanical and electrical protection against environmental stressors.
Technical Parameters
Service Conditions
- Installation environment: Outdoor installation
- Altitude: <=1000 m
- Ambient temperature: -25°C to +40°C
- Relative humidity: Daily average <= 95%, monthly average <= 90%
- Pollution class: Class II (standard) or Class III (W2 variant)
- Environmental conditions: Suitable for outdoor exposure; no severe mechanical shock or vibration
Technical Data
| Rated primary current (A) |
Accuracy classed combination |
Rated Output (VA) |
Short-time thermal current (kA/s) |
Rated dynamic current (kA) |
||
|---|---|---|---|---|---|---|
| 0.2 | 0.5 | 10P15 | ||||
| 5 | 0.5/10P15 0.2/10P15 0.2/0.5 0.2/0.2 |
30 | 50 | 50 | 0.375 | 0.95 |
| 10 | 0.75 | 1.9 | ||||
| 15 | 1.12 | 2.9 | ||||
| 20 | 1.5 | 3.8 | ||||
| 30 | 2.25 | 5.7 | ||||
| 40 | 3 | 7.6 | ||||
| 50 | 3.75 | 9.6 | ||||
| 75 | 5.62 | 14.5 | ||||
| 100 | 7.5 | 19.2 | ||||
| 200 | 11.25 | 28.7 | ||||
| 300 | 15 | 38.3 | ||||
| 400 | 22.5 | 57.5 | ||||
| 600 | 30 | 76.5 | ||||
| 800 | 45 | 115 | ||||
| 1000 | 45 | 115 | ||||
| 1200 | 45 | 115 | ||||
| 1500 | 45 | 115 | ||||
Installation & Wiring
Installation Diagram
The transformer must be securely mounted on a stable foundation using the fixing holes on its metallic base. Primary connections can be made via threaded studs or copper busbars depending on the current rating. Maintain adequate clearance for insulation, heat dissipation, and routine inspection access. Ensure oil level and temperature indicators on the conservator remain visible and accessible.
Outline Dimensions
| Primary Current Range (A) | Thread Size (Stud) | B Dimension (mm) (Busbar) |
|---|---|---|
| 5 â 500 | M22 x 1.5 | 410 |
| 600 â 1000 | M27 x 1.5 | 440 |
| 1200 â 1500 | M30 x 1.5 | 440 |
Selection & FAQs
Selection Guide
- Choose standard or W2 by site pollution. Use the required specific creepage and pollution standard, not only the Class II/Class III label, especially for coastal or industrial sites.
- Select from the detailed 5A–1000A electrical table. Dimensions extend to 1500A, but 1200A–1500A accuracy, burden and fault data are not provided and need a separate schedule.
- Resolve the protection-class inconsistency. The page mentions both 10P15 and 10P20 while the output header assigns 50VA to 10P20; specify the exact class per core.
- Confirm the fixed 5A secondary burden. Include relay or meter input, long outdoor cable runs, terminal resistance and test equipment; a 1A option is not published.
- Approve oil and mechanical interfaces. Confirm oil type/volume, sealing, dielectric tests, conservator indicators, bushing, base, M22/M27/M30 studs, clearances, lifting and grounding.
Frequently Asked Questions
Q1: Can this outdoor current transformer operate at high altitudes and extreme temperatures?
Yes, subject to site verification. It supports altitudes up to 1000m and ambient temperatures from -25°C to +40°C. Contact us for high-altitude derating details.
Q2: Which accuracy class combinations are available for metering and protection?
Standard combinations include 0.2/10P15, 0.5/10P15, 0.2/0.5, and 0.2/0.2. Rated outputs are 30VA for 0.2, and 50VA for 0.5 and 10P15. Specify your exact ratio requirements during inquiry.
Q3: How is the short-time thermal current rating determined for this model?
The rating scales with primary current, ranging from 0.375 kA/s at 5A to 5.62 kA/s at 75A. Dynamic current ratings correspondingly range from 0.95 kA to 14.5 kA.
Q4: Why choose the W2 variant for polluted industrial environments?
The W2 variant provides Class III pollution resistance, compared to the standard Class II. It ensures reliable outdoor performance in heavily contaminated areas. Specify the W2 model for harsh environments.
Q5: What factory tests are performed before shipping the 35kV current transformers?
Standard routine tests are conducted to ensure basic performance and insulation integrity. Specific type tests or special factory acceptance tests are subject to confirmation. Contact our sales team for detailed test reports.
Q6: Are custom primary current ratings available for specific substation projects?
Custom ratios outside the standard 5A to 75A range can be manufactured based on project requirements. Lead times and minimum order quantities are subject to confirmation. Please provide your single-line diagram for evaluation.
Q7: When is this 35kV current transformer suitable for outdoor installation?
It is designed for outdoor 35kV power systems, commonly used in substations for current measurement and relay protection. Ensure the installation site lacks severe mechanical shock or vibration. Ideal for standard outdoor substation applications.