Oil Transformer

Different strategies should be adopted for the routine maintenance of oil-filled transformers based on the frequency of maintenance work. Check out the following sections for valuable guidance on establishing maintenance schedules for daily, weekly, monthly, and yearly tasks.

Daily Procedures
These are the maintenance procedures that must be implemented daily to keep an oil-filled transformer in working condition. The daily routine maintenance schedule includes inspecting the transformer’s temperature, electrical performance, and noise level, as described below:
●Oil and Temperature: To perform daily checks on the transformer’s temperature, inspect the ambient, oil, and winding temperatures and compare them against rated values. The oil level gauge indicator should vary with temperature changes. If the oil level gauge is a magnetic model, the indicator should rotate in the presence of a test magnet. If the indicator does not respond in either case, it must be replaced.
●Electrical Performance: To evaluate the transformer’s electrical performance, daily checks should include inspecting the load voltage and current values and comparing them against rated figures. The load settings dictate which type of transformer can be used to supply power. Due to its importance, a transformer is often protected by differential, overcurrent, and ground-current relays that must be monitored and maintained daily. Using the wrong transformer or failing to maintain protective relays can lead to electrical damage or equipment failure.
●Noise Level: While noise is a more prominent performance indicator for dry-type transformers, the noise level emitted by an oil-filled transformer’s coils, core, and cooling system can also be used to evaluate its performance. If an oil-filled transformer emits loud noises during operation, it is important to promptly identify the source of the noise and measure it using the following three techniques:
1.Sound Power Level Method
2.Sound Intensity Method
3.Sound Pressure Level Method

Weekly and Monthly Procedures
Some maintenance procedures must be implemented weekly or monthly to maintain the working condition of an oil-filled transformer. The weekly routine maintenance schedule should include the following tasks:
●Check the oil level gauge against the oil temperature to analyze the oil level inside the transformer.
●Conduct a full visual inspection of the transformer’s exterior for signs of chipped paint and discoloration.
●Inspect the Buchholz relay for signs of gas collection.
●Ensure that the gaskets, radiators, and joints are tight, with no signs of oil leakage.
●Inspect the seals of all cover-mounted pressure-relief devices.
●Investigate the operation of all pressure-relief devices.
Some maintenance work should be performed monthly or quarterly unless needed sooner. Such routine maintenance schedules should include the following tasks:
●Check the dielectric strength of the transformer oil and top off the oil as required every few months.
●Inspect the transformer terminal bushings and cable box for damage and tightness every few months.
●Check the bushings for cracks every month and during yearly inspections.
●Inspect and clean the transformer accessories and auxiliary circuits every six months.
●Collect transformer oil samples and periodically test them for moisture, acidity, deterioration, discoloration, and other properties to determine whether the oil needs to be filtered or replaced.
●Perform Dissolved Gas Analysis (DGA) on the oil samples to identify the types of gases dissolved in the oil. This can be done on-site if the testing equipment is available or by sending the samples to a laboratory. The most common gases found in transformer oil samples include hydrogen, oxygen, methane, ethane, carbon monoxide, acetylene, and ethylene.

Yearly Procedures
A yearly maintenance schedule should include the measures already discussed in the daily, weekly, and monthly schedules, along with additional tasks for components requiring less frequent maintenance. These tasks may require the assistance of transformer repair and maintenance professionals. The yearly routine maintenance schedule should include the following tasks:
●Check the pressure-relief valve, cover-mounted pressure-relief device, Schrader valve, and surge relay once a year for damage and operational efficiency.
●Check the off-circuit selector and temperature indicators annually. Replace any components that are damaged or not functioning properly.
●Assess the condition of the transformer protective relays and measure their insulation resistances.
●Clean the marshaling boxes and ensure that their weatherproof seals are undamaged.
●Check the condition of the fan and oil-pumping motors and their resistances.
●Examine the top of the transformer near the pressure-relief tank for leaks every three to five years.

Oil-Filled Transformer Maintenance Checklist
Preparing a maintenance checklist before performing maintenance on the oil-filled transformer can make the process much easier and ensure that all necessary steps and requirements are fulfilled. A checklist can assist both in-house and outsourced workers from trusted companies in performing their duties. The following steps are some basic items to check off the list during the maintenance process to ensure a thorough job:
●Ensure that the transformer is de-energized and offline before performing any maintenance work.
●Visually inspect the equipment for any rust, dirt accumulation, chipped paint, or discoloration.
●Listen to the unit when it is energized for any signs of abnormal vibrations or noise.
●Clean the transformer and remove all signs of dust, debris, and dirt.
●Check the transformer temperature and oil level indicators.
●Inspect all cables, bolts, and hardware for tightness. Tighten anything that may be loose.
●Re-energize the transformer before performing tests and analyses, such as breakdown voltage testing or infrared temperature analysis.
●Inspect the transformer for signs of leakage. If found, address the leak immediately. If a transformer leaks frequently, it may be better to fully replace the unit. Common sources of transformer oil leaks include bad gaskets, improperly welded points, and rust on the bottom of the unit.
●Record all events and conditions of the maintenance work. For example, note down the names of the workers, which parts of the transformer they worked on, and how and when they performed their maintenance duties.

Pad Mounted Transformer
In general, Pad mounted transformers are equipment mainly used for the distribution of energy. Our pad mounted transformers are connected to underground utility distribution lines, to reduce the primary voltage to the secondary voltage to be supply to the final customer.
These type of transformers are normally installed outdoor, placed on a pedestal, inside a tank made by mild steel material or stainless steel material, with two doors and a door lock to guarantee their safety.

Distribution Transformer
Distribution transformers are important equipment in the distribution network and power supply and distribution systems of industrial and mining enterprises. One of the main advantages is the compact structure, small size, low noise, and this oil type transformer has an hermetically sealed type and conservator type.

This oil type transformer is applicable in a mine, petrol chemical and other power distribution systems.

Mineral oil is the most used for this type of oil transformers. Among other insulating liquids you can also find vegetable oil.

Power Transformer
This transformers are the main component in the electrical grid. The oil transformer has a huge capacity, so in that way will save a lot of electrical energy, minimize power loss and this make reduce the costs of the clients at the same time. Also in this case, the oil in the transformer helps to the durability and electrical properties of transformer equipment.

Small Substation Transformer
Small substation transformer is another kind of oil type transformer. As we mentioned before, the oil helps transformer to extend their life and avoid damages.

JINSHANMEN TECHNOLOGY CO., LTD(JSM for short) is located at 795 Nanming Road, Shuige Industrial Park, Liandu District, Lishui City. It is a domestic transformer industry production enterprise that integrates domestic and foreign high-tech. The company has advanced production equipment and strong technical strength. Its products have passed the ISO9001:2008 international quality system certification and the National Electrical Product Quality Supervision and Inspection Center, meeting IEC and national standards, as well as obtaining relevant certificates such as production licenses, national safety marks, and explosion-proof certificates.