Description

“NTPL” MAKE 60KV COMPACT TYPE AUTOMATIC OIL INSULATION TEST SET WITH PRINTER TYPE-OTAUC060-S2-PRNT

 

SCOPE:

”NTPL” make  60KV Compact Type Automatic Oil Insulation Test Set is ideal for speedy and accurate testing of  dielectric strength of transformer and circuit breaker oil in room condition in accordance with essential features of IS6792 & IEC156. The Test Set can be used indoor as well as outdoor where power supply of suitable capacity is available. 

PRINCIPLE OF OPERATION:

The Test Set will be Microcontroller based compact type with built-in printer and menu driven.

TECHNICAL FEATURES:

Input Power Supply    :              230Volts, 1 ph. 50Hz AC.

Output Voltage            :              Continuously variable from 0 to 60 KV AC with center point of HV winding grounded ie. (30KV-0-30KV).

Duty Cycle                      :              The OT Set will be designed for Intermittent rating, as per requirement of test intervals.

Nature of Cooling      :              The Transformer will be Cast Resin

Electrodes                     :              Spherical /Cylindrical & Mushroom type detachable.

 

The Test Set consists of……………

• Power Mains ON-OFF operation is done by means of an illuminated ON-OFF switch along with fuse protection.
• ‘EMERGENCY OFF’ push button.
• KEYBOARD: Key matrix will be provided to select mode of testing standard, sequence of operation etc.
• PRINTER: One built-in 24 column dot matrix printer will be provided.
• MAGNETIC STIRRER: For Oil circulation within the Test vessel.

Isolation transformer for control operation, auxiliary supply to power supply for electronic PCBs.

 

INDICATIONS

• ‘HT ON’ lamp indication.
• Lamp indication for ‘STIRRING ON’, ‘END OF TEST’ & ‘TEST PASS/FAILURE’.

 

DISPLAY:

One LCD display and key pad will be provided to set programs.

• Measuring Accuracy: +5%+ 0.1KV
• Resolution: 0.1KV

 

This LCD will indicate the   following:

 

• No. of Test Specification selected
• Mode of Operation (As listed in Table 01 )
• Initial Stand time in secs.
• Rate of Rise of voltage in KV/secs.
• Stir Time Test Duration in secs.
• Stand Time Test Duration in secs
• No. of cycles.
• Individual Break Down Voltage (Vpeak/√2)
• Arithmetic mean breakdown voltage

 

INTERLOCK:

• Zero start interlocking will be provided to ensure that the HV circuit cannot be energised unless the regulator is initially kept or brought back to zero position.
• HT CHAMBER Door interlocking will be provided to ensure that the HV circuit cannot be energised unless the transparent cover of the oil cell placement chamber is closed.
• Minimum & maximum position interlock will be provided so that limit switch will automatically disconnect ‘INCREASE/DECREASE’ circuit of motor connection at maximum and minimum position respectively

 

PROTECTION:

• Besides main switch & fuse in the input side, one CT and contactor provides a snap acting automatic tripping of HV circuit in case of over load or break down of oil sample under test. On tripping the last applied test voltage will be latched & indicated in the LCD.
• Double ground protection will be provided.
• Electromagnetic shielding of High Voltage Test set. 

 

MODE OF OPERATION:

Microcomputer control test sequence for programmable operation will be as follows for BDV mode.

• Mode of Test Specification selected.
• HV is switched ON automatically.
• Rate of rise of voltage automatically selectable for corresponding test specification.
• Controller isolates HV circuit when oil sample fails.
• After break down bubble free vortex stirring starts and stirring continues for the time stipulated in the test specification selected.
• After stirring liquid can be settled for a programmable period of duration required for the test specification.
• of test cycles completed and average breakdown voltage latched.

 

HV TRANSFORMER:

High voltage transformer ratio is 230V/60KV with center point of the HV winding grounded (30KV-0-30KV). The transformer is designed to withstand frequent momentary spark over or short circuit condition caused by the voltage break down of the oil under test. HT winding of the transformer is of graded insulation and CAST RESIN type.

 

Table-1

SL. NO.	TEST SPEC.	ELECTRODE SHAPE	INITIAL STAND (SEC)	RATE OF RISE OF TEST VOLTAGE (KV/SEC.)	INTERMEDIATE		NO. OF TESTS	REMARKS
					STIR (SEC.)	STAND (SEC.)
1	5 mins.test	Spherical	60	2	30	30	3	Test till break down
2	IEC 156	Mushroom/ Spherical	300	2	120	120	6	– Do –

 

GENERAL ARRANGEMENT

The set will be comprising of the following viz. HV Transformer, Control circuit & Test cell with electrode and gauge. All the components will be housed within MS cabinet powder coated and provided with caster wheels and handles for easy movement. A transparent cutout with suitable interlocking device will be provided for covering the HT end of HV Unit. The Set cannot be energised unless this HT end is covered. The oil cell is to be placed between the HV terminals. HV Unit will also be of MS cabinet powder coated provided with caster wheels and handles for easy movement.

 

TEST VESSEL:

The Test Vessel (oil cell) fitted with (i) two brass spheres of diameter between 12.5 to 13 mm or (ii) Mushroom Electrode or (iii) cylindrical electrode placed at a distance of 2.5 mm, on sides of test vessel made from non-absorbent insulating material. Gap can be adjusted by adjusting one sphere, the other being fixed. Dimensions liberal and generally as per IS: 6792 – 1972.A ‘GO / NO-GO’ gauge will be supplied along with cell to adjust the gap distance.

 

ACCESSORIES:

1. Mains Power cord
2. Oil Test cell with electrodes
3. GO and NO GO gauges
4. Magnetic Stirrer

 

DOCUMENTS:

The following documents will be provided along with the test set.

• Performance verification report of the set with indicating display and outputs verified against standard works instruments traceable to accredited laboratory.
• Operation Manual.
• Warrantee Certificate.