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Introduction
For outdoor metering systems in the 20 kV to 22 kV range, combined instrument transformers are often selected to simplify the metering point and reduce the amount of separate primary equipment that has to be mounted, wired, and maintained. That benefit is real, but only when the CT and VT sections are reviewed as one coordinated measuring assembly rather than as two unrelated ratings on the same nameplate.
The JLS-20KV belongs to that category. It is typically considered for outdoor distribution and substation metering where the project uses a combined current-and-voltage measurement unit and where regional practice may describe the system as either 20 kV or 22 kV. In international work, that naming difference matters less than the actual system data, insulation requirements, and metering arrangement stated in the approved project documents.
Where the JLS-20KV Fits Best
The JLS-20KV is generally a good fit for outdoor metering points where a compact combined assembly is preferred over separately mounted CTs and VTs. Typical applications include utility billing interfaces, compact outdoor substations, industrial distribution feeders, and rural distribution projects where installation simplicity and integrated metering layout are both valuable.
Because some markets define this voltage band as 20 kV while others work with 22 kV distribution practice, the better engineering description is not just the model code. It is the full application context: actual nominal system voltage, required measurement accuracy, secondary wiring arrangement, and outdoor service conditions.
Why the V/V Connection Matters in Practice
One of the most important technical points in this product type is the voltage transformer arrangement. The JLS-20KV uses a V/V configuration built from two single-phase VT units, which can be a practical and economical approach in outdoor three-phase metering systems. That configuration is common, but it should still be reviewed against the intended metering philosophy, neutral arrangement, and the type of voltage information required by the downstream instruments.
In other words, the VT section should not be accepted automatically just because the nominal voltage class looks right. The project should confirm that the chosen connection arrangement matches the meter, the panel design, and the utility or owner requirements for voltage measurement.
CT and VT Selection Should Be Reviewed Together
For combined transformer assemblies, the biggest specification mistake is often reviewing the current ratio and voltage ratio separately. In practice, the metering point succeeds or fails as a complete system. That means the CT burden, VT burden, secondary cable run, meter input characteristics, sealing requirements, and test access should be checked together before the order is finalized.
This is especially important for outdoor metering where the combined assembly is expected to support revenue measurement or high-confidence operational monitoring. A technically sound selection is usually based on the actual connected burden and circuit arrangement, not only on standard catalog values.
Oil-Immersed Construction and Outdoor Suitability
The JLS-20KV uses an oil-immersed structure, which remains a familiar and practical choice for many outdoor metering installations. In the right application, oil insulation can provide stable dielectric performance and durable service in exposed environments. At the same time, the project should still review transport handling, sealing quality, moisture control, and maintenance expectations before treating the product as interchangeable with a dry-type or cast-resin design.
That review is worth doing early, especially in environments with strong sunlight, high humidity, seasonal temperature variation, or limited maintenance access. Outdoor suitability depends on more than the nominal voltage class.
How to Think About 20 kV and 22 kV Project Compatibility
For international readers, it is useful to separate naming practice from technical suitability. A product identified by the manufacturer as 20 kV class may still be considered in 22 kV systems if the approved insulation, ratio, and service requirements align with the project documents. The same logic works in the other direction. What matters is not whether one market labels the feeder 20 kV and another labels it 22 kV, but whether the equipment is being selected against the real system data and required standards.
That is why it is usually better to write the specification in functional terms, such as outdoor metering for 20 kV and 22 kV class distribution systems, with final configuration to be confirmed against the nameplate and approved technical schedule.
Practical Points Before Final Approval
Before a combined metering transformer is approved, the engineering team should review several practical details: terminal arrangement, cable routing, meter cabinet interface, burden allocation, and the intended inspection or sealing process. These details often determine whether the unit performs smoothly in service or becomes awkward to commission and maintain later.
If the installation is part of a utility handover point or a project with formal revenue metering requirements, those practical checks deserve even more attention. A clean installation layout and consistent metering configuration often matter as much as the transformer’s headline ratings.
Conclusion
The JLS-20KV is best selected as a complete outdoor metering assembly for 20 kV and 22 kV class systems, not as a generic catalog substitute. A stronger engineering outcome usually comes from reviewing the V/V voltage arrangement, CT and VT duties, connected burden, and outdoor service conditions together, then confirming the final configuration against the approved project documents and product datasheet.
Product Reference
For the base product configuration, source images, and original model details, refer to the JLS-20KV product page.