Technical Parameters

Service Conditions

• Installation environment: Outdoor installation with protection from direct weather exposure
• Altitude: ≤ 1000 m (higher altitude shall be specified for engineering confirmation)
• Ambient temperature: −25 °C to +40 °C
• Relative humidity: Daily average ≤ 95%, monthly average ≤ 90%
• Environmental conditions: Suitable for outdoor use; resistant to moisture, dust, and pollution; withstands normal mechanical shock and vibration in distribution environments
• Pollution severity: Suitable for moderate pollution environments (site-specific assessment required for heavy industrial areas)

Technical Parameters

The JLSZW-10 is a three-phase combined outdoor instrument transformer for 10 kV class AC systems (50 Hz), featuring cast-resin insulation and designed for operation within an ambient temperature range of −25 °C to +40 °C at altitudes up to 1000 m. It complies with applicable standards for measurement accuracy and short-circuit withstand capability, supporting primary current ratios from 5–200 A.

Voltage Transformer Data

Current Transformer Data

Frequently Asked Questions

Q1: Can this 10kV combined transformer be installed in high humidity environments?

Yes, it is suitable for outdoor use with high moisture resistance. It withstands daily average relative humidity up to 95% and monthly averages up to 90%. Confirm specific site conditions with our engineering team.

Q2: What primary current ratios are available for this combined instrument transformer?

The JLSZW-10KV supports primary current ratios ranging from 5 A to 200 A. Select the ratio based on your maximum load current and measurement requirements. Contact us to specify your exact ratio needs.

Q3: How does high altitude affect the installation of this 10kV transformer?

Standard models are rated for altitudes up to 1000 meters. For installations exceeding this limit, derating or special design modifications are required. Please provide your exact site altitude for engineering confirmation.

Q4: Which pollution severity levels can this outdoor voltage and current transformer handle?

It is designed for moderate pollution environments with cast-resin insulation. For heavy industrial areas with severe pollution, site-specific assessments and custom insulation upgrades are necessary. Request a technical evaluation for your specific location.

Q5: What documentation is provided with the combined transformer shipment?

Standard delivery includes basic operation manuals and nameplate data. Specific test reports, certificates of conformity, and warranty documents are subject to order confirmation. Please specify your documentation requirements during the inquiry stage.

Q6: Where is the JLSZW-10KV three-phase combined transformer typically applied?

It is primarily used in 10 kV class AC power systems for outdoor measurement and protection. The cast-resin design ensures reliable operation in standard distribution environments. Verify system compatibility with our technical support.

Q7: What is the operating temperature range for this 10kV instrument transformer?

The JLSZW-10KV operates reliably in ambient temperatures from −25 °C to +40 °C. Its cast-resin insulation provides stable performance across these thermal variations. Confirm extreme climate requirements with our engineering department.

Installation & Wiring

Outline Dimensions

The outline dimensions shown above provide critical mounting and clearance information for the JLSZW-10 three-phase combined transformer. These drawings detail overall physical size, mounting hole positions, primary terminal locations, and secondary wiring access points to ensure proper installation on poles or walls in outdoor environments.

Selection & FAQs

Selection Guide

• Specify voltage and current transformer ratios (e.g., 10000/100 V and 100/5 A) according to system requirements.
• Define accuracy classes for both VT (e.g., 0.2 / 0.5) and CT (e.g., 0.2S) based on metering or protection needs.
• Indicate rated burden (in VA) for each secondary core of both VT and CT to ensure compatibility with connected devices.
• Select the appropriate connection scheme—standard V/V is typical for three-phase three-wire systems without neutral.
• Confirm environmental conditions such as temperature range, altitude, and pollution level if they deviate from standard ratings.
• State any special requirements including IP rating, terminal arrangement, documentation language, or certification needs at ordering stage.

Frequently Asked Questions

Q1: How do I correctly select the VT and CT ratios, accuracy classes, and burden ratings for the JLSZW-10 to ensure compliance with revenue metering standards in a 10 kV distribution network?

For revenue-grade metering per IEC 62053-22 or GB/T 17883, specify a CT accuracy class of 0.2S (not standard 0.2) to maintain ±0.2% error from 5% to 120% of rated current—critical for variable-load commercial/industrial sites. Pair this with a VT accuracy class of 0.2 for voltage measurement. Select VT ratios (e.g., 10000/100 V) matching your system’s phase-to-phase voltage, and CT ratios (e.g., 100/5 A) based on maximum expected load current with 20–30% margin. Ensure total connected burden (watt-hour meters, RTUs, etc.) does not exceed the rated output: 30 VA per VT core and 10 VA per CT core at cosφ = 0.8 lagging. Exceeding burden degrades accuracy and may violate regulatory requirements.

Q2: What are the key technical differences between the JLSZW-10 combined transformer and using separate outdoor VTs and CTs, particularly regarding accuracy, space, and system reliability?

The JLSZW-10 integrates two cast-resin VTs and two CTs in a single V/V-configured enclosure, reducing footprint by ~40% compared to discrete units—critical for pole-mounted or space-constrained substations. Electrically, it maintains equivalent accuracy (0.2S CT / 0.2 VT) but eliminates inter-unit wiring errors and phase misalignment risks. However, combined units offer less flexibility: you cannot independently upgrade or replace VT/CT sections. Reliability is enhanced through unified environmental sealing (IP54+), but a fault in one section may necessitate full unit replacement. For new smart grid deployments prioritizing compactness and installation speed, the JLSZW-10 is advantageous; for legacy retrofits requiring modular redundancy, discrete transformers may be preferable.

Q3: What are the critical installation precautions to avoid accuracy degradation or safety hazards when mounting the JLSZW-10 outdoors on a utility pole or substation structure?

First, verify phase sequence (A-B-C) during primary conductor routing—reversed phases cause negative power readings. Second, never leave CT secondaries open-circuited during energization; always short and ground terminals 1S1–1S2 before disconnecting meters. Third, ensure VT secondary circuits are never fused on the neutral leg in V/V configurations, as this can create floating potentials. Mount the unit vertically per dimensional drawings, maintaining ≥250 mm clearance from grounded surfaces to prevent flashover. Use torque-wrench tightened lugs (typically 15–20 N·m) on primary terminals to avoid thermal hotspots. Finally, route secondary cables in shielded conduits grounded at one end to mitigate EMI in smart metering applications.

Q4: How should I interpret the insulation level “12/42/75 kV” for the JLSZW-10, and what site conditions require derating or alternative specifications?

The notation “12/42/75 kV” defines: Um = 12 kV (maximum system voltage), ACWV = 42 kV (1-min power frequency withstand), and BIL = 75 kV (lightning impulse withstand). This aligns with standard 10 kV class systems per IEC 60071. However, if installed above 1000 m altitude, dielectric strength decreases by ~1% per 100 m; for 2000 m sites, request a BIL ≥85 kV variant. In heavy industrial or coastal areas (pollution severity IV per IEC 60815), specify increased creepage distance (>25 mm/kV) or silicone-hydrophobic coating—standard JLSZW-10 assumes moderate pollution (class II–III). Always validate insulation coordination with local utility overvoltage studies.

Q5: Can the JLSZW-10 support dual-use applications (metering + protection), and what modifications are needed to meet relay coordination requirements?

The base JLSZW-10 is optimized for metering (0.2S/0.2 accuracy) and lacks dedicated protection-class CT cores (e.g., 5P10/10P15). To support overcurrent or earth-fault relaying, you must order a custom variant with an additional CT core wound for protection class—this increases physical size and cost by ~15–20%. Crucially, protection cores require separate secondary windings with higher saturation margins; sharing the 0.2S core risks CT saturation during faults, causing relay misoperation. Confirm with the manufacturer that dynamic current rating (Idyn = 2.5 × Ith) meets your breaker’s interrupting duty. Never use the metering core for protection without explicit engineering validation.

Q6: What maintenance and troubleshooting steps should field engineers follow to diagnose accuracy drift or insulation failure in an operational JLSZW-10 unit?

Begin with non-intrusive checks: inspect for cracked resin, terminal corrosion, or moisture in terminal boxes—common causes of intermittent errors. Perform secondary injection tests: inject 1 A into CT secondaries and verify primary-side voltage drop <1 V (indicating no open circuits); for VTs, apply 100 V to secondaries and confirm primary impedance >1 MΩ. If metering discrepancies persist, conduct ratio and polarity tests per IEC 61869-2/-3. Insulation resistance should exceed 1000 MΩ (500 V DC) between windings and ground. Note: cast-resin units rarely fail internally unless subjected to repeated lightning surges or mechanical impact—suspect external wiring or meter faults first. Replace only if factory test reports cannot be replicated onsite.

Q7: How does the choice between 50 Hz and 60 Hz operation affect performance parameters like burden tolerance and temperature rise in the JLSZW-10?

While the JLSZW-10 supports both frequencies, core losses increase by ~15–20% at 60 Hz due to higher hysteresis and eddy currents in the silicon steel. This reduces effective thermal margin: continuous operation at 60 Hz requires derating connected burden by 10% (e.g., max 27 VA for VT instead of 30 VA) to maintain ≤55 K temperature rise per IEC 61869. Additionally, magnetizing current rises at 60 Hz, potentially affecting 0.2-class accuracy near minimum load. Specify 60 Hz at ordering so the manufacturer adjusts core lamination thickness and air gap—do not assume 50 Hz units are interchangeable in 60 Hz grids without verification.

Q8: What procurement considerations—lead time, cost drivers, and alternatives—should utilities evaluate when specifying the JLSZW-10 for large-scale smart grid rollouts?

Standard JLSZW-10 units (50 Hz, 10000/100 V, 100/5 A, 0.2S/0.2) typically have 8–12 week lead times; customization (60 Hz, dual CT cores, extended creepage) adds 3–6 weeks. Key cost drivers include accuracy class (0.2S adds ~8–12% vs. 0.5), burden rating (30 VA VT costs more than 15 VA), and certification (KEMA or UL adds 5–7%). For budget-sensitive rural deployments, consider the JLSZ-10 (non-combined, CT-only) paired with separate outdoor VTs—but factor in 20% higher installation labor. Always request batch-specific test reports for accuracy and partial discharge (<10 pC at 1.2×Um)—avoid suppliers offering generic certificates. For interoperability with AMI systems, confirm secondary terminal compatibility with common meter socket standards (e.g., ANSI C12.13).