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Our Specialties
 
Manufacturing of Traction Power Transformer 21.6-30.24MVA,132-27KV.
 
Repairing of Power & Traction Transformer.
 
Overhauling of Power Transformers, Traction Power Transformers and Generator Transformers.
 
Switchgears Services.
 
Repairing of LOCOMOTIVE type HETT-5400-3900KVA for 25KV conventional locomotive Transformer.
 
Erection Testing & Commissioning 765KV Voltage class Auto Transformer & Reactors at Site.
 
EPC Work of Traction Substation & SP, SSP in Indian Railways.
 
Insulation and drying out of Power Transformers and Traction Power Transformers.
 
Condition monitoring of Power Transformers and Traction Power Transformers.
 
Supply of spares.
 
Conservator Modification with Air Cell.
 
Erection Testing & Commissioning of Power Transformers and Traction Power Transformers.
 
 

 

 
 
Welcome to Vishvas Power Engineering Services Pvt. Ltd.

Sr. No.

(1)

Characteristics

(2)

Requirement

(3)

Method of Tests

(4)

Remarks

(5)

i)

Appearance

The oil shall be clear and transparent and free from suspended matter or sediments

A representative sample of the oil shall be examined in a 100 mm thick layer at 27° C

-

ii)

Density at 29.5°C Max

0.89 g/cm 2

IS 1448 (P : 16) : 1977

See Note 1

iii)

Kinematic viscosity, Max, at

a)       27° C

b)      40° C

 

 

 

27 cSt

Under consideration

IS 1448 ( P : 25): 1976

-

iv)

Interfacial tension at 27° C, Min

0.04 N/m

IS 6104 : 1971

-

v)

Flash point Pensky- Marten (closed), Min

140 °C

IS 1448 (P : 21) : 1970

-

vi)

Pour point, Max

- 6°C

IS 1448 (P : 10) :  1970

-

vii)

Neutralization value

a)       Total acidity, Max

b)      Inorganic acidity/ alkalinity

 

 

0.03 mg KOH/G

 

 

Nil

 

 

IS 1448 (P : 2) : 1967

 

 

do

 

Alcoholic potassium hydroxide solution of 0.02 N should be used in place of 0.1 N indicated in test method.

viii)

Corrosive sulphur

Non-corrosive

Annex B

-

ix)

Electric Strength

(Breakdown voltage)

a)       New unfiltered oil, Min

b)      After filtration, Min

 

 

 

30 KV (rms)

 

 

If the above value is not attained. The oil shall be filtered 60 KV (rms)

IS 6792 : 1972

-

 

 

 

 

 

See Note 2

x)

Dielectric dissipation factor (tan d ) at 90°C, Ma

0.002

IS 6262 : 1971

See Note

xi)

Specific resistance (resistivity)

a)       At 90°C, Min

b)      At 27°C, Min

 

 

 

35 x 1012 ohm-cm

 

1500 x 1012 ohm-cm

 

 

xii)

Oxidation stability

a)       Neutralization value after oxidation, Max

b)      Total sludge, after oxidation, Max

 

 

0.4 mg KOH/g

 

 

 

 

 

0.1 percent by weight

 

 

Annex C

 

 

-

xiii)

Ageing characteristics after accelerated ageing (open beaker method with copper catalyst)

a)       Specific resistance (resistivity)

1)      at 27°C, Min

2)      at 90°C, Min

b)      Dielectric dissipation factor (Tan d ) at 90° C, Max

c)      Total acidity, Max

d)      Total sludge, Max

-

 

 

 

 

 

 

 

 

2.5 x 1012 ohm-cm

0.2 x 1012 ohm-cm

0.20

 

 

 

0.05 mg KOH/g

 

0.05 percent by weight

IS 12177 : 1987

Method A

 

 

 

 

IS 6103 : 1971

 

 

 

 

IS 6262 : 1971

 

 

 

IS 1448 (P : 2) : 1967

 

Annex A of IS 12177

-

xiv)

Presence of oxidation inhibitor

The oil shall contain antioxidant additives

IS 13631 : 1992

See Note 3

xv)

Water content, Max

50 ppm

IS 13567 : 1992

-

xvi)

SK value

Under consideration

Annex D

-


Information in Stage Interaction :

IS 335
NEW OIL

Table 1 Schedule of Characteristics
(Clauses 5.1 and 9.1)

Sr. No.

(1)

Characteristics

(2)

Requirement

(3)

Method of Tests

(4)

Remarks

(5)

i)

Appearance

The oil shall be clear and transparent and free from suspended matter or sediments

A representative sample of the oil shall be examined in a 100 mm thick layer at 27° C

-

ii)

Density at 29.5°C Max

0.89 g/cm 2

IS 1448 (P : 16) : 1977

See Note 1

iii)

Kinematic viscosity, Max, at

a)       27° C

b)      40° C

 

 

 

27 cSt

Under consideration

IS 1448 ( P : 25): 1976

-

iv)

Interfacial tension at 27° C, Min

0.04 N/m

IS 6104 : 1971

-

v)

Flash point Pensky- Marten (closed), Min

140 °C

IS 1448 (P : 21) : 1970

-

vi)

Pour point, Max

- 6°C

IS 1448 (P : 10) :  1970

-

vii)

Neutralization value

a)       Total acidity, Max

b)      Inorganic acidity/ alkalinity

 

 

0.03 mg KOH/G

 

 

Nil

 

 

IS 1448 (P : 2) : 1967

 

 

do

 

Alcoholic potassium hydroxide solution of 0.02 N should be used in place of 0.1 N indicated in test method.

viii)

Corrosive sulphur

Non-corrosive

Annex B

-

ix)

Electric Strength

(Breakdown voltage)

a)       New unfiltered oil, Min

b)      After filtration, Min

 

 

 

30 KV (rms)

 

 

If the above value is not attained. The oil shall be filtered 60 KV (rms)

IS 6792 : 1972

-

 

 

 

 

 

See Note 2

x)

Dielectric dissipation factor (tan d ) at 90°C, Ma

0.002

IS 6262 : 1971

See Note

xi)

Specific resistance (resistivity)

a)       At 90°C, Min

b)      At 27°C, Min

 

 

 

35 x 1012 ohm-cm

 

1500 x 1012 ohm-cm

 

 

xii)

Oxidation stability

a)       Neutralization value after oxidation, Max

b)      Total sludge, after oxidation, Max

 

 

0.4 mg KOH/g

 

 

 

 

 

0.1 percent by weight

 

 

Annex C

 

 

-

xiii)

Ageing characteristics after accelerated ageing (open beaker method with copper catalyst)

a)       Specific resistance (resistivity)

1)      at 27°C, Min

2)      at 90°C, Min

b)      Dielectric dissipation factor (Tan d ) at 90° C, Max

c)      Total acidity, Max

d)      Total sludge, Max

-

 

 

 

 

 

 

 

 

2.5 x 1012 ohm-cm

0.2 x 1012 ohm-cm

0.20

 

 

 

0.05 mg KOH/g

 

0.05 percent by weight

IS 12177 : 1987

Method A

 

 

 

 

IS 6103 : 1971

 

 

 

 

IS 6262 : 1971

 

 

 

IS 1448 (P : 2) : 1967

 

Annex A of IS 12177

-

xiv)

Presence of oxidation inhibitor

The oil shall contain antioxidant additives

IS 13631 : 1992

See Note 3

xv)

Water content, Max

50 ppm

IS 13567 : 1992

-

xvi)

SK value

Under consideration

Annex D

-

 

 

NOTES: 

1. Density of the oil may be measured at ambient temperature and converted to 29.5°C using the following equation:
29.5 p – Pt {1 + X (t-29.5)}

Where

t – Ambient temperature (in °C),

pt – Density measured at temperature t, and

x – Correction factor (equal to 65 x 10-5 approximately)

2. As a consequence of the tendency for water absorption to occur due to breathing on storage even when drums are sealed the oil shall be filtered to remove moisture and particulate contaminants preseal in the original sample before the treat as follows :   

‘A sufficient quantity of oil is heated to 90 + 2°C, then filtered hot under vacuum corresponding to an absolute pressure of about 2.5 kpa through a sintered glass filter of porosity grade 4’.

A portion of the filtrate is cooled in desiccators and used immediately to measure electric strength, if required, and specific resistance at 27°C. The remaining hot filtrate is immediately used for measuring dielectric dissipation factor at 90°C and specific resistance at 90°C.

3. For both phenol and amine types of indicators, qualitative method as per Annex D shall be adopted. In case of ambiguity (marginal cases) in finding the intensity of colour, a quantitative method as given in Annex D shall be adopted. Value of 0.5 (Max) shall be treated as absence of DBPC – Phenolic type inhibitor (Quantitative method for amins is under consideration).


 
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