Overview
The LZZW6-10 / LZZW-10/12 is a pillar-type, fully enclosed outdoor current transformer with cast-resin insulation, designed for 10 kV, 11 kV and 12 kV class AC power systems operating at 50 Hz or 60 Hz. Its solid cast-sealing structure ensures reliable dielectric performance under harsh outdoor conditions.
Engineered for measurement (accuracy classes up to 0.2S) and protection (10P), it supports secondary currents of 5 A, 1 A or 2 A per project needs. It meets requirements for outdoor metering, relay protection, and energy metering in exposed environments such as pole-mounted installations, open-air substations, and contaminated areas.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System voltage | 10 kV, 11 kV, 12 kV |
| Rated insulation level | 12/42/75 kV |
| Rated frequency | 50 Hz / 60 Hz |
| Rated secondary current | 5 A / 1 A (2 A optional) |
| Burden power factor | cosφ = 0.8 lagging |
| Accuracy classes | 0.2S, 0.2, 0.5, 0.5S, 10P |
| Insulation type | Fully enclosed cast-resin |
| Installation | Outdoor |
| Pollution class | Class II reference |
Model Designation
- L: Current transformer
- Z: Pillar-type support structure
- Z: Solid cast-sealing insulation
- W: Anti-dirtiness / outdoor anti-pollution design
- 6 / 10: Rated voltage class code
- 10/12: 10 kV catalogue class with 12 kV insulation coordination for 10 kV, 11 kV and 12 kV systems
Construction
The LZZW6-10 / LZZW-10/12 features a monolithic pillar-type body formed by vacuum-cast epoxy resin, fully encapsulating the primary conductor, magnetic core and secondary windings. This solid cast-resin construction provides high mechanical strength, excellent moisture resistance, and stable dielectric properties under outdoor exposure. The outer surface incorporates an anti-pollution profile with optimized creepage distance to withstand dust, humidity, rain and industrial contamination. Secondary terminals are housed in a sealed terminal box with IP-rated protection, ensuring long-term reliability in open-air installations.
Technical Parameters
Service Conditions
- Installation location: outdoor medium-voltage distribution system
- System voltage: 10 kV, 11 kV and 12 kV class networks
- Rated frequency: 50 Hz / 60 Hz
- Rated secondary current: 5 A / 1 A, with 2 A available according to project requirement
- Outdoor anti-pollution requirement: class II reference
- Installation environment: shall be checked for pollution severity, altitude, humidity, temperature, wind load and mounting stability.
- Special application note: For coastal, high-humidity, heavy-pollution or high-altitude applications, creepage distance and insulation coordination must be technically confirmed.
Technical Parameters
The LZZW6-10 and LZZW-10/12 are pillar-type outdoor cast-insulation current transformers designed for 10–12 kV class systems. They feature a rated insulation level of 12/42/75 kV, operate at 50/60 Hz, and support primary current ranges from 20 A up to 3000 A. Compliant with IEC 60044-1 and GB1208-2006, they are suitable for altitudes and environmental conditions requiring Class II anti-pollution performance.
| Rated Primary Current (A) |
Accuracy Class |
Rated Output (VA) |
Short-Time Thermal Current |
Dynamic Current |
|---|---|---|---|---|
| 20–40 / 40 | 0.2S / 0.2 / 10P 0.2 / 10P or 0.5 / 10P 0.5S / 0.5 / 10P |
0.2: 10 0.2S: 10 0.5S: 10 0.5: 15 10P: 15 |
6.3 kA | 15 kA |
| 30–60 / 60 | 9 kA | 22.5 kA | ||
| 40–75 / 75 | 15 kA | 37.5 kA | ||
| 50–100 / 100 | 18 kA | 45 kA | ||
| 75–150 / 150 | 25 kA | 55 kA | ||
| 100–200 / 200 | 50 kA | 110 kA | ||
| 150–300 / 300 | 60 kA | 130 kA | ||
| 200–400 / 400 | ||||
| 300–600 / 600 | ||||
| 400–800 / 800 | ||||
| 500–1000 / 1000 | ||||
| 1200–1500 | 80 kA | 100 kA | ||
| 2000–3000 |
Terminal Configuration
| Terminal Area | Function | Engineering Note |
|---|---|---|
| P1 / P2 | Primary current terminals | Connect according to the outdoor installation drawing and system current direction. |
| S1 / S2 | Secondary current output | Connect to meters, relays or monitoring devices according to polarity. |
| Grounding point | Safety grounding | Grounding shall comply with substation and outdoor equipment requirements. |
| Secondary shorting device | Maintenance safety | Short-circuit the secondary circuit before disconnecting instruments or relays. |
Installation & Wiring
Installation Diagram
The LZZW6-10 and LZZW-10/12 current transformers feature an outdoor pillar-type structure designed for secure mounting on support brackets or bases as specified in the approved outline drawing. Installation must ensure correct primary terminal orientation, adequate phase clearance, proper grounding, and protection of secondary wiring against moisture ingress.
Selection & FAQs
Selection Guide
- Confirm the 10kV, 11kV, or 12kV system class, 12/42/75kV insulation level, and site pollution severity.
- Select the 20A–3000A primary ratio from the load and fault study, then choose a 1A, 5A, or project-specific 2A secondary.
- Specify the number of cores, metering or protection function, accuracy class, and VA burden for each circuit.
- Verify Ith and Idyn for the selected ratio against the prospective short-circuit duty.
- Confirm post-mounting dimensions, conductor load, terminal orientation, grounding, creepage distance, and weatherproof cable entry.
Frequently Asked Questions
Q1: What medium voltage systems support the LZZW6-10 outdoor pillar current transformer?
It supports 10 kV, 11 kV, and 12 kV class networks. The rated insulation level is 12/42/75 kV. Confirm specific network parameters with our engineering team.
Q2: How to install in coastal or high-pollution areas?
Standard models meet Class II anti-pollution requirements. For coastal or heavy-pollution sites, creepage distance and insulation coordination must be technically confirmed. Contact us for customized insulation details.
Q3: Which primary current ranges are available for short-circuit applications?
Primary currents range from 20 A up to 3000 A. Short-time thermal and dynamic current ratings depend on the selected primary current. Request the specific datasheet for exact ratings.
Q4: Are these current transformers compliant with international IEC standards?
Yes, they comply with IEC 60044-1 and GB1208-2006 standards. Factory test reports are provided upon request. Please specify your required certification documents during inquiry.
Q5: Can the rated secondary current be customized for our project?
Standard secondary currents are 5 A or 1 A. A 2 A option is available according to specific project requirements. Confirm your exact secondary current needs before ordering.
Q6: What operating frequencies and accuracy classes does this CT support?
It operates at 50 Hz or 60 Hz frequencies. Accuracy classes and rated outputs vary by specification. Provide your metering or protection requirements for precise class selection.
Q7: Why choose cast-insulation pillar-type CTs for outdoor distribution?
Cast-insulation provides superior moisture resistance and mechanical stability for outdoor medium-voltage systems. It eliminates the need for oil maintenance. Contact our sales team for bulk pricing.