JDZC-3/6/10KV semi-enclosed epoxy resin cast voltage transformer

JDZC-3/6/10KV semi-enclosed epoxy resin cast voltage transformer

3–10 kV Single-phase epoxy resin cast VT/PT for metering, protection, with IEC 61869.

  • Semi-enclosed epoxy resin VT for stable indoor medium-voltage applications
  • 3kV, 6kV, 10kV ratings for distribution, metering, and control systems
  • Accuracy class 0.2 and 0.5 suitable for revenue and technical metering
  • High VA output capacity supports metering, protection, and auxiliary power

Product Overview

The JDZC-3/6/10 series single-phase epoxy resin voltage transformers are precision electromagnetic instruments designed for accurate voltage measurement, energy metering, control circuits, and relay protection in medium-voltage AC power systems. Based on electromagnetic induction principles, these voltage transformers provide galvanically isolated secondary voltage signals proportional to the primary voltage, suitable for 3–10 kV indoor distribution applications.

Key Ratings

The table below summarizes the principal electrical ratings and insulation parameters of the JDZC-3/6/10 series voltage transformers. Final values are subject to order specification and nameplate data.

Item Specification (per order / nameplate)
System voltage class 3 kV / 6 kV / 10 kV class (indoor distribution applications)
Rated frequency 50 Hz (60 Hz available upon request)
Rated voltage ratio 3000/100/220 V, 6000/100/220 V, 10000/100/220 V
Accuracy classes 0.2 or 0.5 for metering applications
Rated output 30-1500 VA per accuracy class as specified
Maximum output capacity 600-3000 VA depending on configuration
Insulation level JDZC-3: 3.6/25/40 kV (Um/Ud/Up)
JDZC-6: 7.2/32/60 kV
JDZC-10: 12/42/75 kV
Applicable standards GB/T 208-2007; IEC 61869-3 (reference)
Creepage distance grade Grade II pollution environment

Working Principle

Operating on Faraday’s law of electromagnetic induction, the voltage transformer features a laminated magnetic core with the primary winding connected to the system voltage and secondary windings wound around the core. The alternating magnetic flux generated by the primary voltage induces a proportional voltage in the secondary winding, delivering standardized output voltage to connected metering, protection, and control burdens.

System Application Position

  • Medium Voltage Distribution: 3-10kV switchgear and distribution panels
  • Energy Metering: Revenue-grade electricity measurement systems
  • Protection Circuits: Overvoltage, undervoltage, and ground fault protection schemes
  • Control Circuits: Voltage signal for control and monitoring systems
  • Operating Power Supply: Auxiliary power for control devices when configured accordingly

Structural Overview

The epoxy resin cast construction with semi-enclosed design ensures reliable insulation performance, moisture resistance, and mechanical strength. The compact mounting configuration supports secure installation in indoor switchgear environments while maintaining required electrical clearance and creepage distances for Grade II pollution conditions.

Model Designation

JDZC 3.6.10 Cast Epoxy Resin Voltage Transformers TYPE

Model Code Explanation

  • J — Voltage transformer (VT)
  • D — Single-phase configuration
  • Z — Cast-resin (epoxy) insulated structure
  • C — Semi-enclosed design
  • 3 / 6 / 10 — Voltage class (kV)

This designation system enables clear identification of insulation structure, enclosure type, and voltage class for engineering selection.

Service Conditions

The JDZC-3/6/10 series voltage transformers are designed for indoor operation under normal service conditions in medium-voltage power systems.

  • Installation environment: Indoor installation only
  • Altitude: Not exceeding 1000 m above sea level (higher altitude shall be specified for engineering confirmation)
  • Ambient temperature: −5 °C to +40 °C
  • Relative humidity: ≤ 85%
  • Creepage distance grade: Grade II pollution environment
  • Environmental conditions: Free from corrosive gases or vapors; free from explosive or flammable media; no severe vibration, mechanical shock, or impact
Engineering Note: The installation location shall comply with applicable electrical safety regulations and provide stable operating conditions throughout the transformer’s service life.

Construction

Construction Design

  • Structure: Semi-enclosed type for indoor switchgear
  • Insulation: Epoxy resin cast insulation system
  • Core: Laminated silicon steel core design
  • System: Integrated primary and secondary winding system
  • Terminals: Primary terminals positioned at top of housing

The epoxy resin casting provides stable insulation properties and resistance to moisture, contamination, and aging for long-term indoor service.

Windings & Terminal Marking

  • Primary terminals: A / X (or U / N for phase notation)
  • Secondary terminals (Measurement winding): a / x (or u / n)
  • Auxiliary secondary terminals (where applicable): ad / xd (or ud / nd)

Terminal markings follow standard VT polarity conventions. Under normal operating conditions, when primary terminal A is positive with respect to X, secondary terminal a is positive with respect to x. Correct terminal identification shall be observed to ensure metering and protection performance.

Technical Data

This section provides selection-oriented technical data for the JDZC-3/6/10 series single-phase, semi-enclosed epoxy resin voltage transformers used in 3–10 kV class AC systems operating at 50 Hz. The data supports preliminary selection of accuracy class, rated output capacity, and insulation coordination.

Definitions: Accuracy class indicates measurement precision (0.2 or 0.5 class). Rated output (VA) is specified per accuracy class. Maximum output is the total burden capacity the transformer can support. Insulation level is expressed as Um/Ud/Up (maximum system voltage / power-frequency withstand voltage / lightning impulse withstand voltage).

Data Reference

Model Rated Voltage
Ratio (V)		 Accuracy Class
Rated Output
(VA)		 Maximum
Output
(VA)		 Rated
Insulation
Level (kV)
Um/Ud/Up
JDZC-3/6/10 3000/100/220
6000/100/220
10000/100/220		 0.2 class: 30 VA
0.5 class: 300 VA		 600 3.6/25/40
7.2/32/60
12/42/75
0.2 class: 30 VA
0.5 class: 400 VA		 800
0.2 class: 30 VA
0.5 class: 500 VA		 1000
0.2 class: 30 VA
0.5 class: 600 VA		 1200
0.2 class: 30 VA
0.5 class: 800 VA		 1500
0.2 class: 30 VA
0.5 class: 1000 VA		 2000
0.2 class: 30 VA
0.5 class: 1500 VA		 3000
Selection Note: The rated output (VA) for each accuracy class shall be selected based on the total connected burden of meters, relays, and wiring losses in the secondary circuit. The maximum output represents the total capacity limit that should not be exceeded under any operating condition.
Application Engineering Support: Application-specific recommendations may include burden calculation, voltage ratio selection, terminal allocation, and switchgear integration guidance based on project specification.

Standards & Normative References

Standard Title Application
GB/T 208-2007 Voltage Transformers Primary national standard for VT requirements
IEC 61869-1 Instrument Transformers – Part 1: General Requirements General requirements (reference)
IEC 61869-3 Instrument Transformers – Part 3: Additional Requirements for Voltage Transformers VT-specific requirements (reference)
GB 311.1 Insulation Co-ordination Insulation level coordination
DL/T 596 Electric Power Equipment Preventive Test Procedures Routine and preventive testing procedures

Factory Test Compliance

  • Routine tests per GB/T 208-2007 requirements (including polarity/marking verification, ratio verification, and accuracy verification per specified class and burden)
  • Dielectric tests per insulation coordination requirements and applicable standard
  • Partial discharge test where specified by the project requirement
  • Visual and dimensional inspection including marking and workmanship conformity
  • Type and special tests as required by the project specification
Compliance Note: All voltage transformers maintain full compliance with listed standards. Test certificates available for each manufactured unit with traceability to accredited laboratories.

Installation & Dimensions

  • Outline dimensions and mounting details are provided in the dimensional drawings.
  • The transformer shall be securely mounted using the designated fixing holes on the base.
  • Primary connections shall be made at the top terminals following proper torque specifications.
  • Adequate clearance shall be maintained for insulation, heat dissipation, and maintenance access.
  • Ensure proper grounding of the transformer core and secondary circuit per applicable safety standards.

Outlines

JDZC 3.6.10 Cast Epoxy Resin Voltage Transformers 600A

JDZC Voltage Transformers 600A

JDZC 3.6.10 Cast Epoxy Resin Voltage Transformers 800 1200VA

JDZC Voltage Transformers 800-1200 VA

JDZC 3.6.10 Cast Epoxy Resin Voltage Transformers 1500 2000VA

JDZC Voltage Transformers 1500-2000 VA

JDZC 3.6.10 Cast Epoxy Resin Voltage Transformers 2500 3000VA

JDZC Voltage Transformers 2000-2500 VA

Dimensional drawings showing mounting dimensions, terminal positions, and clearance requirements shall be provided in the product-specific documentation.

Connection Diagrams

JDZC 3.6.10 Cast Epoxy Resin Voltage Transformers Principle diagram

Safety Notice: Primary circuit must be de-energized and isolated before any maintenance work. Secondary circuits should be properly grounded in accordance with local electrical safety regulations.

Safety Notes

  • One point of the secondary circuit shall be reliably grounded in accordance with applicable standards.
  • Do not exceed the maximum rated output (VA) to prevent overheating and accuracy degradation.
  • Primary terminals are live and shall be treated with appropriate electrical safety precautions.
  • All installation and maintenance work shall comply with local electrical safety regulations.
  • Ferroresonance conditions shall be avoided through appropriate circuit design, grounding practice, and capacitance control.

Ordering Information

When placing an order, the required configuration shall be specified according to the local grid requirements, applicable standards, and project technical specification. The following parameters shall be clearly stated for technical confirmation and production release:

  • Model designation (JDZC-3, JDZC-6, or JDZC-10)
  • Rated voltage ratio (e.g., 10000/100/220 V)
  • Accuracy class requirements (0.2 or 0.5 for metering applications)
  • Rated output (VA) for each accuracy class
  • Maximum output capacity (VA)
  • Insulation level (if special requirements beyond standard values)

For special requirements (partial discharge limits, terminal arrangement, mounting constraints, documentation language, or certificates), specify at ordering stage for technical agreement and final data sheet prior to production.

FAQs

Select voltage ratio based on primary system voltage and required secondary voltage. For 10kV systems, 10000/100 V ratio is standard for single-phase VTs. The secondary voltage of 100V is compatible with most standard meters and relays. For line-to-line voltage measurement in three-phase systems, coordinate the ratio with the connection scheme (open delta, wye-wye, etc.).
Accuracy class indicates the maximum permitted voltage error under rated conditions. 0.2 class provides ±0.2% voltage error and ±10 minutes phase displacement error, suitable for revenue metering. 0.5 class provides ±0.5% voltage error and ±20 minutes phase displacement error, suitable for general metering and protection applications. Selection depends on application requirements and applicable standards (e.g., revenue metering requires 0.2 class per most utilities).
Rated output (VA) shall cover total connected burden including all meters, relays, control devices, and wiring losses in the secondary circuit. Calculate burden for each device (VA = V × I for each connection) and sum all connected loads. Add 20-30% margin and select the next higher standard rated output value. Ensure the maximum output capacity is not exceeded.
Insulation level is specified as Um/Ud/Up where Um is maximum system voltage (rms), Ud is power-frequency withstand voltage (rms, 1 min), and Up is lightning impulse withstand voltage (peak). Standard values are: JDZC-3: 3.6/25/40 kV, JDZC-6: 7.2/32/60 kV, JDZC-10: 12/42/75 kV. Compliance is verified through factory dielectric tests per GB/T 208-2007 with test certificates provided.
Yes, when properly configured with adequate output capacity. The auxiliary secondary winding can provide operating power for control circuits. However, the total burden (metering + protection + control) must not exceed the maximum rated output capacity. Verify that voltage regulation and transient response meet control circuit requirements.
One point of the secondary circuit shall be reliably grounded to prevent dangerous voltages from appearing on secondary circuits due to primary insulation failure. Grounding shall be performed at a single point only (typically at the x or n terminal) in accordance with GB 50062 and local safety regulations. Multiple grounding points can cause circulating currents and measurement errors.
Nameplate and factory test report prevail for acceptance. All units are tested per GB/T 208-2007 routine test requirements. Type test reports are available for the series. Individual unit test certificates are issued with each shipment showing ratio verification, accuracy verification, dielectric test results, and partial discharge measurements (where applicable). Certificates are traceable to accredited laboratories.