69KV VOLTAGE TRANSFORMER SAMPLE TECHNICAL SPECIFICATION

69KV VOLTAGE TRANSFORMER SAMPLE TECHNICAL SPECIFICATION
Sample specification of a 69kv Voltage Transformer.

Description:
The unit should be magnetic type and for connection between phase and earth in networks with isolated or earthed neutral.

• Designed with low flux density in the core and can therefore be operated at 190% rated voltage for more than 8 hours
• Fitted with a secondary measuring winding and a tertiary earth-fault winding
• Hermetically sealed, which means no need for regular maintenance procedures
• Primary terminals shall be suitable for connection of copper or aluminum connectors.
• All external parts are hot-dip galvanized
• High seismic withstand capability (0.5G)

For Oil-Filled Type:
The unit shall be hermetically sealed and of the minimum oil-filed type and compact design. All sealing shall be located below the oil level. The expansion room shall be of a gas cushion type filled with nitrogen. Oil level should be of the reflection type and without moving parts. The external ferrous parts shall be of hair pin type insulation consisting of oil-impregnated paper and capacitor layers for voltage grading. The unit must be able to be tilted to 60 deg. C.

For Gas Type:
The primary and secondary winding of the SF6 Gas Insulated shall be housed in a non-corrosive cylinder hermetically sealed type, preventing any contact of the SF6 with the atmosphere by means of separate flexible diaphragm.

The instrument transformer shall have the following built-in devices:
• A Pressure Relief Device that is set to trigger at the designed over-pressure value.
• An SF6 Gas Pressure Indicator with pressure graduations showing the Normal and High/Low danger levels of SF6 Gas Pressure.
• Pressure switches with two (2) sets of NO/NC contacts for connection with the Substation Alarm/Protection Circuits.
 - One (1) set of contacts calibrated to trigger at Low Pressure Alarm Level
- One (1) set of contacts calibrated to trigger at Low Pressure Danger Level

Type Outdoor Type, Minimum Oil-filled or Gas Insulated
Cooling Oil-immersed/ Gas insulated, self-cooled
Construction Single phase, Inductive type, Single bushing
Termination Line-to-ground
Accuracy Class 0.3 or better through burden W up to Y for both cores & taps
Compliance to Standard   ANSI/IEEE C57.13 or applicable IEC
Nominal System Voltage, KV     69
Maximum Continuous System Voltage, KV 72.5
BIL, KV      350
Rated Frequency, Hz    60

Rated withstand & Test Voltage, KV
• Low frequency withstand, KV RMS 140
• Impulse lightning withstand, KV crest  325

Minimum creepage distance   1725 mm
No. of core     Two (2)
Single Ratio (L-G)    40250V : 115V
PTR      350 :1
Available secondary voltage   115V
Mounting      Pedestal
Post Insulator Characteristics
• Voltage class, KV   72.5
• Color      Chocolate brown (preferred)
• Creepage Length, mm   1725
Weight      320 kgs. (maximum)

Accessories:
• 1-set Primary Connectors, clamp type terminal of nickel-plated brass for horizontal connection of round aluminum or copper conductors.
• Secondary Connectors, 1 set- M10 split studs with 3.2 mm slot suitable for conductors of 8 mm2 across section with nuts for connecting cable lugs
• Grounding Connectors split studs, 1 set-Earthing clamp for a round conductors or line of 5-16 mm diameter.
• There should be provisions for the installation of security seals on the secondary terminal box. (e.g. seal holder, etc.)

REQUIREMENTS/CONDITIONS
• Factory test results and Type Approval Test Report of the PT from an independent regulating body or international organizations.
• Field reference, catalogues, drawings, hardware and instruction user’s manual.
• Declaration and proof that the manufacturer should have been in the business of manufacturing the equipment of not less than ten (10) years.