Phone:
(701)814-6992
Physical address:
6296 Donnelly Plaza
Ratkeville, Bahamas.
High Voltage Instrument Transformer
Current transformers and voltage transformers serve different secondary circuits. Compare the CT and VT paths by ratio, accuracy duty, burden and terminal arrangement before choosing a unit for a meter or relay.
High-voltage instrument transformers
Indoor CT and JDZ-10 VT
Specify CT current ratio and secondary current, or JDZ-10 primary and secondary voltage. Set accuracy and burden for the connected meter or relay.
CT / 10 KV INDOOR
03 CT housing and terminal images
10 kV Indoor Cast-Resin Current Transformer
Epoxy-cast indoor CT providing a specified 1 A or 5 A secondary current for metering or protection circuits. Select ratio and accuracy to match the connected device.
JDZ-10 / INDOOR VT
04 VT images · one construction illustration
JDZ-10 Indoor Voltage Transformer
Single-phase indoor VT with 10 kV primary and listed 100 V or 100/√3 V secondary options for voltage input to meters or protection devices.
Instrument transformer details
Product details
CT / 10 KV INDOOR
10 kV Indoor Cast-Resin Current Transformer
Specify the CT ratio, secondary current, accuracy, connected burden and terminal scheme for the metering or protection circuit.
CT and VT serve different secondary circuits. Select this CT against its own meter or relay requirement.
Series image 1 of 3
Allow space for the primary connections, mounting base and secondary terminals in the panel layout.
CT specifications
Specify ratio, accuracy, burden, core arrangement and terminals together. Use a combination confirmed by the rated-data sheet for the complete CT model.
| Item | Value / option |
|---|---|
| Rated voltage | 10 kV |
| Primary current options | 100 / 200 / 400 / 630 / 1000 A |
| Secondary current options | 5 A or 1 A |
| Accuracy options | 0.5 / 1.0 for metering; 5P / 10P for protection |
| Insulation and site | Epoxy-resin cast; indoor |
| Rated frequency | 50/60 Hz |
CT circuit and panel requirements
- Meter or relay inputProvide the device input, required ratio and metering or protection duty.
- Secondary circuitState the connected burden, cable run and any separate metering or protection core.
- Panel interfaceShare primary conductor, mounting space, polarity and terminal details.
JDZ-10 / INDOOR VT
JDZ-10 Indoor Voltage Transformer
Select the JDZ-10 secondary voltage, accuracy and rated burden for the meter or protection device. Check the primary connection and terminals against the circuit diagram.
CT and VT serve different secondary circuits. Select this VT against its own meter or relay requirement.
Series image 1 of 4
Specify the primary connection, secondary winding schedule and terminal positions for the VT panel circuit.
VT specifications
Specify voltage ratio, accuracy, rated burden, winding arrangement and terminals together. Use a combination confirmed by the rated-data sheet for the complete VT model.
| Item | Value / option |
|---|---|
| Primary voltage | 10 kV |
| Secondary voltage options | 100 V or 100/√3 V |
| Rated burden options | 20 / 50 / 100 VA |
| Accuracy options | 0.2 / 0.5 / 1.0 |
| Type and site | Single-phase; indoor |
| Rated frequency | 50/60 Hz |
VT circuit and panel requirements
- Voltage inputProvide the primary connection scheme and meter or relay secondary voltage.
- Measurement dutyState accuracy requirement and the connected burden, including wiring.
- Panel interfaceShare the cubicle envelope, mounting and terminal arrangement.
Instrument transformer construction
Two secondary-signal paths
A current transformer and a voltage transformer feed different signals to meters and relays. Review their primary connections, secondary circuits and panel interfaces separately.
10 kV indoor · current transformerCTPrimary current
to instrument current
to instrument current
Signal path 01 / 02
Indoor cast-resin CT
An indoor CT provides a specified secondary current for metering or protection. The primary conductor, mounting and marked terminals must fit the selected switchgear assembly.
- Primary interface
- Check the feeder conductor route, installation position, mounting and polarity markings against the proposed CT and panel drawings.
- Secondary circuit
- Match the 1 A or 5 A option, accuracy duty and connected burden to the meter or relay. Confirm whether separate metering and protection cores are required.
10 kV indoor · voltage transformerJDZ-10Primary voltage
to instrument voltage
to instrument voltage
Signal path 02 / 02
JDZ-10 single-phase VT
The JDZ-10 provides a secondary voltage for measurement or protection devices. Confirm its primary connection, secondary winding arrangement and terminals for the selected circuit.
- Primary interface
- Set the primary connection and installation position from the project circuit diagram; check insulation, clearances and mounting on the selected-unit drawing.
- Secondary circuit
- Choose the listed 100 V or 100/√3 V output for the connected device. Verify accuracy, rated burden and winding arrangement as a complete model configuration.
Provide a complete rating schedule for each CT core or VT winding, together with outline and terminal drawings.
Specification process
Specify the CT or VT for its circuit
Start with the primary circuit and meter or relay input, then review each instrument transformer’s ratings, secondary connections and panel fit.
From circuit data to a matched unit
- 01
Define the primary circuit
For a CT, provide primary current and feeder duty. For a VT, provide system voltage and the primary connection scheme.
- 02
Match the secondary input
State the meter or relay input. Specify the CT current ratio and required cores, or the VT voltage ratio and required windings.
- 03
Set accuracy and burden
List metering or protection duty for each output, required accuracy and connected burden, including the secondary wiring.
- 04
Review panel and approval data
Check outline dimensions, mounting, primary clearances, polarity and terminals. Request the rated-data sheet and test records for the quoted CT or VT.
Circuit drawings and device inputs define the electrical requirement; panel drawings establish fit and connections.
Signal and rating comparison
Compare indoor CT and JDZ-10 VT
Specify ratio, accuracy, burden and connection details for each CT core or VT winding to match the connected meter or relay.
| Review point | 10 kV indoor CT | JDZ-10 indoor VT |
|---|---|---|
| Primary quantity | Feeder current. Primary current options are 100 / 200 / 400 / 630 / 1000 A; choose the ratio for the circuit duty. | Primary voltage is 10 kV. Confirm the primary connection scheme and voltage ratio for the circuit. |
| Secondary output | 1 A or 5 A secondary current. Match the selected output to the meter or relay current input. | 100 V or 100/√3 V secondary voltage. Match the selected output and connection to the device voltage input. |
| Accuracy duty | 0.5 / 1.0 metering and 5P / 10P protection options. Specify each duty and the required core arrangement. | 0.2 / 0.5 / 1.0 accuracy options. Confirm the accuracy requirement and winding arrangement for the connected device. |
| Burden check | Provide the connected meter or relay burden and secondary wiring contribution. Confirm the rated burden for each selected CT core. | Rated burden options are 20 / 50 / 100 VA. Check the connected devices and wiring against the rating of the quoted winding. |
| Installation fit | Indoor epoxy-cast construction. Check conductor geometry, mounting, primary clearances and panel space. | Single-phase indoor unit. Check the primary connection, mounting, clearances and available cubicle space. |
| Connection drawings | Review polarity markings, core identification and secondary terminals on the selected-unit drawing. | Review primary connections, winding identification and secondary terminals on the selected-unit drawing. |
Quotation information
Information for a CT or VT quotation
Provide each instrument transformer’s circuit, secondary input and panel interface. Mark fixed requirements and any ratio or connection decisions still open.
Useful project files
Include the single-line and secondary diagrams, meter or relay data, rating schedule and panel layout. A replacement request also needs the existing nameplate and terminal drawing.
Application context
Instrument transformer applications
Review current and voltage signal requirements for metering, protection and replacement within an existing panel.
01Metering signal channels
Current channel
CircuitPrimary current
SignalCT
DeviceMeter current
Voltage channel · where required
CircuitSystem voltage
SignalVT
DeviceMeter voltage
Ratios and accuracy follow the connected meter’s requirements
Current and voltage for metering
A CT supplies the meter’s current input. A VT supplies a voltage input where the metering scheme requires one. Specify the two signal channels separately.
Design considerations
Match each ratio, secondary input, accuracy and connected burden to the meter. Review the CT core or VT winding arrangement and the terminal diagram for each selected unit.
02Protection signal channels
Current channel
CircuitPrimary current
SignalCT
DeviceRelay current
Voltage channel · where required
CircuitSystem voltage
SignalVT
DeviceRelay voltage
Confirm each core or winding’s duty on the quoted data sheet
Inputs for protection relays
The relay scheme defines its current and voltage inputs. Select the CT for the specified protection duty; review a VT input when that scheme calls for one.
Design considerations
Specify CT protection class, current ratio and connected burden. For a required VT channel, confirm the voltage ratio, accuracy, winding and burden against the relay requirements.
03Existing panel interfaces
CT review
RatingCT data
SignalCurrent output
PanelCT fit
VT review
RatingVT data
SignalVoltage output
PanelVT fit
Review rated data and dimensions for each proposed replacement
Replacing a panel instrument
Existing nameplate data and circuit drawings define the required CT or VT output. Review the replacement’s electrical data together with its fit inside the panel.
Design considerations
Compare ratio, accuracy, burden and core or winding requirements. Check mounting points, primary clearances, conductor geometry, polarity and terminal positions against the selected-unit drawing.
Specification questions
Questions before selecting a CT or VT
CT and VT duties, secondary outputs, terminal connections and panel replacement.
When does a circuit need a CT, a VT or both?
A CT provides a current signal; a VT provides a voltage signal. The metering or protection scheme determines which inputs are needed. Specify each instrument separately against the connected meter or relay and its circuit diagram.
How should ratios and secondary outputs be specified?
For a CT, give the primary current, current ratio and required secondary current input. For a VT, give the system voltage, primary connection scheme, voltage ratio and required secondary voltage input. Confirm the selected combination on the proposed unit’s data sheet and connection drawing.
Can one accuracy class define the complete instrument?
Specify the metering or protection duty, accuracy and burden for each required CT core or VT winding. Include the connected device burden and secondary wiring contribution. The quotation should identify the core or winding arrangement and rated burden for each proposed output.
How should primary and secondary connections be documented?
For a CT, show the primary conductor, polarity markings, core identification and secondary terminals. For a VT, show the primary connection, winding identification and secondary terminals. Include the mounting and outline drawing for the panel layout.
What must be checked for a panel replacement?
Provide the existing nameplate and primary and secondary drawings. Review ratio, accuracy, burden and core or winding duties alongside mounting points, conductor geometry, clearances, polarity markings and terminal positions. Confirm electrical requirements and physical fit on the proposed replacement drawings.
Which documents and scope details help prepare a quotation?
Share the single-line and secondary diagrams, meter or relay data, rating schedule and panel layout. State CT and VT quantities separately, required accessories and delivery needs. List the data sheets, outline and terminal drawings, test records and project requirements needed for review, and identify any open selections.