power transformer solutions for oilfields

In oilfield ground construction projects, oil-immersed power transformers are mostly used. The model is mostly S11-M. This model is a fully-sealed oil-immersed power transformer. That is, from the appearance point of view, there is no oil pillow on the traditional transformer. Transformers are used more and more widely because of their high reliability, long service life, and simple operation and maintenance.

A Complete Guide to Oil Immersed filled Distribution Transformer

In oilfield surface construction projects, the voltage levels of dual-winding oil-immersed power transformers are mainly 10/0.4kV, 35/10(6)kV, 110/35kV, etc. This article focuses on the selection of 10/0.4kV oil-immersed power transformers in oilfield surface construction.

A Complete Guide to Oil cooled transformer

Table of Contents
power transformer solutions for oilfields
power transformer solutions for oilfields

What is distribution transformer winding?

Classified by phase number

  • Single-phase transformers—used for single-phase loads and three-phase transformer groups;
  • Three-phase transformer used for step-up and step-down of a three-phase system.

Distribution Transformer Solution for Papermaking Enterprises

Classified by insulating medium

  • Dry-type transformers-rely on air convection for cooling;
  • Oil-immersed transformer-rely on oil as the cooling medium. Such as oil-immersed self-cooling, oil-immersed air-cooling, oil-immersed water-cooling, forced oil circulation, etc.

Distribution Transformer Capacity Solution for Processing Factory

Classified by purpose

  • Power transformer-used for step-up and step-down of power transmission and distribution system;
  • Instrument transformers—used for measuring instruments and relay protection, such as voltage transformers and current transformers;
  • Test transformer-can generate high voltage and perform high voltage test on electrical equipment;
  • Special transformers-such as electric furnace transformers, rectifier transformers, etc.

Distribution Transformer Selection of An Office Building

Classified by winding form

  • Double winding transformer—used to connect two voltage levels in the power system;
  • Three-winding transformer—used in power system regional substations to connect three voltage levels;
  • Autotransformer—used to connect power systems with different voltages. It can also be used as an ordinary step-up or step-down transformer.

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Features and applications of power transformers

The insulating medium of dry-type power transformer is resin or paper and insulating paint, and the cooling method is self-cooling and air-cooling. Its advantages are maintenance-free, lighter weight, impact resistance, convenient handling, etc., but its disadvantages are limited capacity, low overload capacity, and high cost. Generally, it is installed indoors and arranged in the same room as the low-voltage power distribution cabinet. It is mostly used in indoor places such as hotels, office buildings, and high-rise buildings.

The insulating medium of oil-immersed power transformers is transformer oil, and the cooling methods include self-cooling, air-cooling, and forced oil circulation cooling. Its advantages are good cooling effect, wide application range of capacity, high overload capacity, high operation stability, low price, etc. The disadvantage is that it is not easy to carry. Generally installed in a separate transformer indoor or outdoor.

Selection principle of 10kV power transformer

Selection of the number of power transformers

The number of installed power transformers should be selected according to load characteristics and economic operation. When one of the following conditions is met, two or more transformers should be installed:

  • There are a large number of primary or secondary loads;
  • Seasonal load changes greatly;
  • The concentrated load is relatively large.

The Most Complete Guide of 10 kv transformer

According to the above selection principle: the first-level electrical load in the oilfield station uses a dual power supply, and two transformers are selected; the second-level electrical load uses a dual-circuit power supply, and two transformers are selected; the third-level electrical load uses a single power supply. , Choose to install a transformer.

The types of oilfield stations are mainly divided into several types: joint stations (also known as centralized oil and gas treatment stations), crude oil transfer stations, sewage treatment stations, water injection stations, metering stations, sewage lifting stations, etc. In addition, mechanical oil production wells are common.

Capacity selection of power transformer

The capacity of the power transformer should be selected according to the following principles:

(1) The transformer capacity should be selected according to the calculated load. The calculation of the calculated load generally adopts the need factor method.

(2) According to the results of load calculation, when a single transformer is selected, the load rate of a single transformer is generally 60%-85%.

(3) According to the results of the load calculation, when selecting two transformers, the load rate of a single transformer is generally 55%-70%, and for transformers with a larger primary and secondary load ratio, it can be 50%.

(4) For stations with electrical loads for fire pumps, the calculated loads in the stations should be calculated separately according to the following methods, and the larger value should be used to calculate the transformer capacity:

  • The sum of the maximum calculation load except for the fire pump and the calculation load of the largest fire pump.
  • The sum of the calculated load of the fire-fighting facilities and the primary electricity load in the station.

(5) When determining the configuration plan of the pumping unit well transformer, the transformer should be selected based on the well spacing and the pumping unit motor capacity, and after technical and economic comparison, the average load rate of the pumping unit transformer should not be less than 30%.

Verify the bus voltage drop when the motor starts

Verification principle

When the motor is started, the voltage on the distribution bus should meet the following requirements:

  • In general, when the motor starts frequently, it should not be lower than 90% of the nominal voltage of the system; when the motor starts infrequently, it should not be lower than 85% of the nominal voltage.
  • When there is no lighting load or other load sensitive to voltage drop on the distribution bus and the motor does not start frequently, it should not be less than 80% of the nominal voltage.
  • When the power distribution bus is not connected to other electrical equipment, it can be determined according to the conditions of ensuring the starting torque of the motor; for lower than the motor, it should also be ensured that the voltage of the contactor coil is not lower than the release voltage. In our daily design, it is mostly the above-mentioned situation (1), and the motors are mostly started infrequently. Therefore, the bus voltage drop should be checked according to the motor starting at no less than 85% of the nominal voltage.

The calculation of the voltage drop when the motor starts is mainly in the following two situations: one is powered by a system with infinite power capacity (ie, system voltage power), and the other is powered by a system with limited power capacity (ie, generator power).

The following focuses on the method of verifying the voltage drop of the system with infinite power capacity.

As we all know, the common starting methods of motors are full voltage starting, soft starter starting and variable frequency starting. When the motor is started at full voltage, the starting current is 5-7 times the rated current of the motor; when the soft starter starts, the starting current is 2 to 5 times the rated current of the motor; when starting with a variable frequency, the starting current is equal to the rated current of the motor.

4 Responses

  1. A fascinating discussion is worth comment. I do think that you should write more
    about this issue, it might not be a taboo matter but generally people don’t
    discuss these issues. To the next! Kind regards!!

  2. I like how you mentioned that the transformer should be chosen based on the well spacing when planning the configuration plan of the pumping unit. My uncle mentioned to me last night that his friend is hoping to find a transformer for his upcoming project and asked if I have any idea what is the best option to do. Thanks to this informative article and I’ll be sure to tell him that they can consult a well-known transformer supplier company as they can answer all their inquiries.

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