Tag Archives: transformer oil purification

Extention of transformer service life time: how to?

Power transformers are the most widely used elements of power plant and power distribution systems. Operation of transformers is an important factor in reliability of power transformation, distribution and transmission.

Most transformer currently in operation are either nearing their projected service life, or have already exceeded it. Full scale replacement of all such equipment is not feasible due to the obviously prohibitive costs. This makes the issue of transformer service life extension quite important. Is there a solution? The answer is yes.

During operation, the transformer undergoes both irreversible and reversible changes. The former include thermal oxidation of winding insulation, various internal damage, which requires disassembly of the equipment to repair and replace the failed components. However, many performance characteristics can be restored entirely on site.

Care about transformer oil is care about the transformer

Petroleum based transformer oil is widely used as dielectric an heat dissipation agent in many electrical systems. Analysis of transformer failure and damage shows that the service life of transformer is defined by the condition of the insulation.

During operation the oil accumulates various contaminants and aging products. In the presence of oxygen and water the dielectric fluid oxidizes even in ideal conditions. This process causes the formation of acids, which react with carbon and metal, forming aldehydes, alcohols, soaps etc.

Contaminated oil thickens and increases viscosity. This degrades the heat dissipation capability, reducing the transformer life time.

The optimal solution is oil reclamation. The reclamation process removes contaminants and decomposition (aging) products from the oil, restoring the essential operational parameters.

GlobeCore has developed and put into production the CMM-12R units, specifically for extension of transformer life time by restoring the dielectric strength and chemical composition of the electrical insulation oil.

СММ-12R operation principle: fuller’s earth filtration of mineral oil

The CMM-12R units regenerate and restore transformer oil by percolation of the oil through Fuller’s earth sorbent: it’s fuller’s earth filtration. Beside, this system can heat, degas, dry and filter the dielectric fluid. Sorbent reactivation occurs alonig with processing of the oil – inside the unit. After reactivation the Fuller’s earth can be used normally.

DSCN73192

The СММ-12R is connected directly to the transformer tank, forming a closed oil circulation line: the oil to be regenerated flows into the unit, processed oil flows back into the transformer. The flow of oil, along with vibration and heat in the transformer, also facilitates removal of contaminants from cellulose insulation.

After GlobeCore’ oil reclamation process, the oil is chemically identical to new dielectric fluid. Additives improve the oil’s oxidation stability, further extending its service life.

Advantages of СММ-12R unit for oil reclamation:

  • mobility and onsite operation;
  • oil reclamation without taking the transformer offline and setting up tanks for oil transfer and storage;
  • reactivation of sorbent directly in the unit. The sorbent can be reactivated up to 300 times, the equivalent of 1,5-2 years of operation;
  • removal of both solved and unsolved contaminants from the used oil;
  • process automation. The system operates according to the program and does not require operator intervention;
  • operator comfort (separate work place, PC controls, ventilation);
  • optional equipment to control oil level in the transformer, a generator for autonomous operation, inhibitor injection section to add oxidation stabilizer into the oil.

Specifications of CMM-12R for Oil Reclamation

Parameter

Value

1 Capacity, m3/hour, min

4

2 Processed oil parameters:
Moisture by weight, g/t(ppm) as per IEC 733; ASTM D-1533

5

Filtration, µm

5

Volumetric gas content in % as per IEC 60599; ASTM D-3612

0,1

Acid number, mg KOH/g as per IEC 296; ASTM D-664

0,01

Corrosive sulfur, ISO 5662; ASTM D-1275

None

Dielectric strength, kV, IEC 156; ASTM D-1816

70

Interfacial tension, N/m, at 25ºС, ISO 6295; ASTM D-2285

45

Dissipation factor at 90ºС, IEC 247; ASTM D-924

0,001

Oxidation stability

Acid number, mg KOH/g,

IEC 1125А; IEC 1125B; IP-307

0,2

3 Max oil output temperature in heating mode, ºС

90

4 Outlet pressure, bar, not less than

1,5

5 Oil heater power, kW, not more than

54

6 Max power consumption, kW

69

7 Power parameters
voltage, V

380

AC frequency, Hz

50

Client benefits after purchasing the unit for fuller’s earth filtration:

  • complete restoration of transformer oil;
  • extension of transformer life time from 20 to 35 years;
  • significant reduction of storage space required for waste oil;
  • saving on buying new oil and disposing of waste oil;
  • training of client’s personnel;
  • Starting and commissioning of the unit by our engineering team on site (if necessary);
  • qualified consulting by GlobeCore experts during operation of the oil reclamation unit.

GlobeCore equipment can be in stock or custom design. Stock models can be purchased directly from the factory’s warehouse. Custom orders require 45 work days lead time.

Reliability of Low Voltage Power Transformers

GlоbeCоre’s oil reclamation technology has been proven to cost effectively regenerate transformer oil thereby increasing the operational reliability of electric transmission equipment.

Before electric grid restructuring started, units with a voltage of between 110 and 500 kV (kilovolt) had constituted the greatest part of the fleet of transformers.  But the things have recently changed, today power companies routinely use transformers with voltage that is less than 110 kV with the majority of the transformers having a capacity of  less than 35 kV.

Table 1 analysis of the reasons for equipment damage depending on the point of fault.

Table 1

Damage Sources for Transformers with Voltage up to 35 kV

No.

Type of Fault

Rate of the total % of faults

1 Winding faults

19

2 Bushing insulator

3

3 Insulation faults

21

4 Insulation moistening

8

5 Oil

5

6 Voltage regulators

23

7 Contacts in windings

15

9 Other

6

As we can see, the greatest amount of damage is the result of insulation faults. That is why the condition of transformer oil is of such importance.  The efficiency of the entire insulation system (both solid and liquid) largely depends on the quality and condition of the dielectric transformer oil.  Such factors as temperature extremes, interaction with the atmospheric oxygen, and the accumulation of emulsion water have a negative impact not only on the performance characteristics of oil, but also on the condition of the solid insulation.  As a result, transformers break down prematurely even though their service life should be much longer.

Unfortunately, once the transformer has experienced a catastrophic failure,  there is only one solution to this problem.   The failed transformer willl have to be replaced by a new one.  But, such a strategy requires significant capital expenditures and leads to reduced profits and inefficient operations.

The solution to this problem is to call GlоbeCоre who is in the business of designing and producing equipment for purification and regeneration of transformer oils.

GlobeCore promotes and adheres to the principle of “preventive maintenance.”  That means that the causes of transformer damage are prevented in the first place during transformer servicing.  It is transformer oil purification that helps insulting oil maintain its performance characteristics at the proper level and slows down the process of its aging.

GlоbeCоre produces equipment that allows for complete processing of transformer oil (purification, dehydration, and degasifying) to restore the original performance characteristics of the dielectric oil.

GlоbeCоre equipment is also very eco-friendly: there are no harmful discharges into the air since it uses the sorbent that can be reactivated to prevent the penetration of oil residues into water and soil.  The service life of transformers with a voltage up to 35 kV may be extended by 10 years if negative impacts are reduced.

GlobeCore representatives particiapted in a seminar in Jordan

The company’s professionals attended a seminar in Amman, Jordan, on 15 April. The meeting was focused on equipment to improve efficiency of transformer operation.

GlobeCore’s Daria Shaddad and Yevheniy Svirid presented the main types of equipment which the company can offer for Jordan’s power plants.

Regeneration of Oil

Oil Regeneration today has become a very interesting and important subject.  Oils can be regenerated in a number of ways by different equipment and to varying degrees of purification.

GlobeCore has developed and built oil regeneration equipment for many different applications that involve regeneration and purification.  The equipment varies widely in terms of number of applications and the degree of regeneration desired by the operator and include the following:

  • oil regeneration
  • heat and vacuum purification of oil,
  • purification of oil by adsorbents
  • drying of transformer windings,
  • dehydration of oil,
  • degassing of oil,
  • reactivation and preparation of sorbents, including full regeneration of MINERAL oils with color lightening.

The following is a brief list of GlobeCore’s equipment for oil regeneration, putificaton and other industrial applications.

  • Themovacuum oil purification units, mobile oil plants: СММ-0.6; СММ-0.7(Р); СММ-0.6; СММ-1.0; СММ-1.7; СММ-2.2; СММ-4.0; СММ-4.3 and some other models;
  • Comprehensive oil restoration units, including heating, nitrogenation, drying and filtration of insulation oils: CMM-3, CMM-4, CMM-5, CMM-5М, CMM-6, CMM 10-10, CMM 10-10В, CMM 10-10Л, CMM 10-10М, CMM-12B, CMM-12B1, CMM-12B2, CMM-12B3, CMM-14B У1, CMM-14B1, CMM-14B2, CMM-10-3, CMM-10-3Е, UDV-2М, PDV-Е and other range.
  • units for purification, drying and removal of solids from transformer and turbine oils – MCU-2-U1, MCU-4-U1, MCU-4С-U1,  MCU-4А,  MCU-4СА,  MCU-4C, MCU-4CF, MCU-4CS,  MCU-4CSA, MCU-А, MCU-С, MCU 4Р-N, MCU 4Р-NС, MCU 4Р-NA, MCU 4Р-NСА,  BC-N, MCU-7, FSM-2, FSMB-110М etc;
  • Sorbent regeneration systems– BR, PS-1, PS-1А,  PS-1Е, BRPS, MCU-4Р-BR, zeolite drying cabinet
  • Systems and vacuum sections for drying of solid insulation of power transformers – “Iney-4″, ” Iney-4М”, ” Iney-5″, ” Iney 5М”, ” Iney-6″, ” Iney-4.1″, ” Iney-4.1М”, ” Iney-4.2″, ” Iney-4.2М”, vacuum units BV-1 and BPR;
  • Units for drying of air to dew point below -50°С – “Sukhovey”, ” Sukhovey-4″, ” Sukhovey-5″, ” Sukhovey-4Е” with two independent heaters
  • transformer and transformer oil heating units: NTML, NTML-160М, NTML-80М, NTML-120М, NTML-200М, NTML-240М, NTML-150Е, for parameters of processed oil: solid content no more than 5 (10) ppm, filtration from 5 to 20 micron
  • oil filtration systems – FUM-P, FUM-А, customized drying and solid removal systems for mineral oils up to 50 m3/hour capacity, purity class from 7 toо 11, filtration ratios from 20 to 2000, filtration fineness 1, 3, 5, 10, 20 and 40 micron;

The full range of GlobeCore products is presented in the attached file, and can also be seen on the company’s website at www.globecore.com

The company has a global dealership network, and the products are supplied to more than 80 countries world wide.  Certified explosion protection option is available. Production certified in accordance with ISO 9001 – 2000.