JLSZV-35kv High-voltage Metering Combined Instrument Transformer | Outdoor Dry-type Wide-load Electric Energy Metering Equipment

Overview

The JLSZV-35kv high-voltage metering combined instrument transformer (called an electric energy metering box when equipped with meters) is suitable for electric energy metering on 50Hz or 60Hz three-phase AC power grids with a rated voltage of 35kV. It is installed on the high-voltage side of the supply transformer. The instrument box contains three-phase active and reactive watt-hour meters, or an active/reactive combined electronic meter. It is a metering device used to directly measure active and reactive energy in high-voltage lines. It plays an important role in preventing tampering, saving energy, and strengthening power supply management. All indicators comply with national standards GB20840.2-2014, 20840.1-2010, GB20840.3-2013 and enterprise standard Q/YCD003-2003. The product has passed inspection by the National Transformer Supervision and Inspection Center and is a recommended product approved by the State Economic and Trade Commission for the third batch of national urban and rural power grid construction and renovation. The product can replace oil-immersed electric energy metering boxes. The JLSZV-35kV high-voltage metering combined instrument transformer meets the high-current, high-precision metering requirements of 35kV. The rated insulation level complies with GB 20840 standards, making it suitable for gateway metering in substations and large user installations.

Product Model and Meaning

Structure Introduction

The JLSZV35 series three-phase outdoor, dry-type, wide-load combined instrument transformer (called a metering box when equipped with meters) uses outdoor epoxy resin cast insulation for its unit components. The unit components are assembled into an integrated (or split) structure, giving the product advantages such as UV resistance, aging resistance, and rain resistance. The product can be made with single, double, or triple current ratios, and the high accuracy of the 0.2S class ensures accurate metering under wide loads. Double and triple current ratios use a secondary tapping structure.

Three-phase two-element electric energy metering box (combined instrument transformer)

The three-phase three-wire combined instrument transformer (two-element) consists of two single-phase voltage transformers (PT) and two current transformers (CT). Both PT and CT are electromagnetic types. The two PT windings use a V/V connection to form a three-phase measurement device. The primary windings of the two CTs are connected in series with phase A and phase C of the power grid respectively. A grounding screw is welded to the bottom mounting bracket.

Three-phase three-element electric energy metering box (combined instrument transformer)

The three-phase three-element electric energy metering box (combined instrument transformer) with Y/Y0 connection is a new generation product improved from the three-phase two-element VV connection. As society continues to develop, the load conditions of the power grid are also constantly changing. For example, single-phase rectification in electrified railways, electric furnace smelting, rectifier electrolysis, etc., as well as harmonics and phase load imbalances in the power grid, may cause negative sequence or harmonics without a path in the V/V connection, resulting in inaccurate metering (measured Y/Y0 connection can increase revenue by 3%-15%). Therefore, our factory has newly developed a metering box with Y/Y0 connection to ensure accurate metering under complex operating conditions, supporting current reforms in power management. This metering box has flexible metering features. For example, using single-phase meters can monitor the operating status of each phase load to identify problems in time. If the load varies greatly, please use S-class current transformers (metering range from 1% to 120% of rated current) together with wide-load meters such as 1.5A-6A to avoid the trouble of frequently changing ratios.

The instrument box is connected to the secondary windings of the combined instrument transformer. The instrument box contains one three-phase active watt-hour meter and one three-phase reactive watt-hour meter, or a three-phase active/reactive combined energy meter. The readings can be clearly seen through the observation window.

This series of products has the following structural features:

(1) The JLSZV-35 series combined instrument transformer is assembled from dry-type unit components, eliminating the problem of oil leakage, thus achieving oil-free operation;

(2) Both voltage and current are cast with resin in a modular structure, making replacement and maintenance easy and cost-effective;

(3) The product has high accuracy, with current transformers achieving 0.2S class, enabling wide-load metering;

(4) The materials used give the product high dynamic and thermal stability;

(5) The voltage part can be equipped with a 220V auxiliary winding to provide power for switches, etc.

Main Technical Parameters

Voltage Part Main Technical Parameters

Current Part Main Technical Parameters

Note: For dual-ratio specifications: The secondary current for dual ratios is indicated. The current ratios are 1S1, 1S2, 1S3; 2S1, 2S2, 2S3. Connecting 1S1, 1S2; 2S1, 2S2 gives the smaller current ratio. Connecting 1S1, 1S3; 2S1, 2S3 gives the larger current ratio. The current ratio connection should be selected according to the corresponding transformer capacity.

Voltage Transformer Error Limits Table

Current Transformer Error Limits Table

Outline and Base Installation Dimensions (unit: mm)

JLSZV-35W "V/V" connection three-phase three-wire two-element

Ensure that the JLSZV-35kv high-voltage metering combined instrument transformer has a rated insulation level compliant with GB 20840 standards. During installation, embed foundation bolts on the horizontal base. Apply conductive paste to the primary terminal contact surfaces. Ground the secondary side to prevent interference. Keep the metering instrument junction box sealed and moisture-proof.