JDZX18 Voltage Transformer with Fuse 6kV 10kV

Description

JDZX18 at a Glance

The JDZX18 voltage transformer with fuse is a single-phase, semi-insulated epoxy-resin unit for indoor 6 kV and 10 kV systems. It carries a primary fuse inside the same cast body, which is the feature that separates it from a plain metering PT and the reason it is specified on circuits where the voltage tap needs its own protection.

The published application is 10 kV and below, in systems with a grounded neutral, for voltage measurement, energy metering, voltage control and relay protection at 50 Hz. Two voltage classes are offered, 6 kV and 10 kV.

Reading the JDZX18 Type Designation

The suffix on this model carries more information than the prefix, and getting it wrong is how buyers end up with an unfused unit.

Technical Data

Ratio, accuracy class and rated output are set at order because they follow the metering and protection scheme rather than the frame. State them with the inquiry and they are built into the winding.

Why the Fuse Sits Inside the Enclosure

The JDZX18 voltage transformer with fuse is a small load on a high-voltage circuit, and a fault in it is a small fault on a big system. The fuse is there to clear that fault before it becomes a busbar event.

• Protects the PT from a secondary short circuit. A shorted secondary overloads the primary winding, and the primary fuse is what interrupts it.
• Isolates a failed winding. If the primary insulation breaks down, the fuse clears the circuit and keeps the fault off the busbar.
• Reduces the number of components in the cubicle. With the fuse inside the cast body, the panel designer does not need a separate fuse holder and its clearances.

The practical consequence is that the fuse rating and type must be fixed at order together with the ratio. A unit quoted without the fuse values is an incomplete quotation, and replacing the fuse later means handling the primary side.

Semi-Insulated or Fully Insulated

This is the decision that most often sends a buyer to the wrong page, so it is worth stating plainly.

The semi-insulated construction of the JDZX18 voltage transformer with fuse is not a cost-reduced version of a fully insulated unit. It is a different design that relies on one end of the primary winding being at or near ground potential, which is why it suits grounded-neutral systems. Specifying it on an ungrounded system is a mismatch that will not show up until the insulation is stressed.

If you need a fully insulated unit without a fuse, see the JDZ10 cast voltage transformer.

Grounded-Neutral 6 kV and 10 kV Systems

The published application is 10 kV and below with a grounded neutral, for measurement, metering, voltage control and protection. Typical installations are switchgear panels, substation metering bays, industrial plant boards and commercial distribution cabinets.

Voltage transformers on a grounded-neutral system see less severe overvoltages than those on an ungrounded system, which is what allows the semi-insulated design. If you are replacing a unit and are unsure of the system earthing, send the single-line diagram: the earthing method decides between this frame and the fully insulated one, and it is not something to infer from the old unit’s part number alone.

Mounting and Outline Dimensions

The JDZX18 voltage transformer with fuse mounts inside an indoor cubicle, with the primary connected to the busbar or the line side and the secondary wiring taken to the meter or relay compartment. The drawing below gives the outline for the frame.

When the JDZX18 Is the Wrong Choice

• Ungrounded or resonant-earthed systems. The semi-insulated design assumes a grounded neutral. Use a fully insulated frame instead.
• Circuits that do not need primary fusing. If the tap is already protected elsewhere, the JDZ10 avoids paying for a fuse you will not use.
• Outdoor installation. This is an indoor frame.
• Voltage classes above 10 kV. The series tops out at 10 kV.

The full range is listed under voltage transformers, and the accuracy and burden relationship between classes is covered in our guide to voltage transformer accuracy and instrument PT selection.

Service Conditions

The published envelope is indoor installation, 50 Hz, and pollution Class II. Where a switchroom runs humid or dusty, the pollution class and the condensation risk belong in the inquiry, because the creepage is fixed during casting.

Altitude correction applies above 1,000 m. Units for higher sites are available but are not the standard build, so state the altitude rather than assuming the standard one will do.

Standards and Routine Tests

Routine tests on every JDZX18 voltage transformer with fuse cover power-frequency withstand, insulation resistance, ratio and polarity, and ratio error and phase displacement at the specified burden. Type test reports covering temperature rise and impulse withstand are available for documentation packages.

Manufacturer Supply, OEM and Wholesale

• Project supply. Units matched to a switchgear bill of materials, with drawings and test reports issued for approval.
• OEM and private label. Nameplate marking and documentation sets under your brand, with ratio, class and fuse ratings fixed to your scheme.
• Wholesale and distributor supply. Repeat orders against a frozen specification, packed for export with current transformers and contactors from the same category.

Price, MOQ and Lead Time

• MOQ. Standard configurations ship from single units. Custom ratios and private-label marking carry a higher minimum.
• Price drivers. Voltage class, ratio, accuracy class, rated output, fuse rating and quantity.
• Lead time. Confirmed against the production schedule at order. Standard ratios move faster than custom windings.
• Payment. Standard terms are a deposit with the balance against the bill of lading copy. Project quantities can be quoted on letter of credit.

What to Send With Your Inquiry

• System voltage and voltage class
• System earthing method: grounded neutral or ungrounded
• Voltage ratio, primary and secondary
• Accuracy class and rated output
• Fuse rating required, or the primary fault level if you want us to size it
• Rated frequency
• Pollution level and site altitude
• Quantity, destination port and required delivery date

Send those through the quote form on this page. The earthing method and the fuse rating are the two items that most often come back as follow-up questions, so including them up front shortens the quotation to one round.

FAQ

Request Quote