RU2485660C2 - Submersible motor with increased power factor - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: submersible motor with increased power factor consists of stator, rotor, node of current lead, hydroprotection system and connected module. The module is designed as a cylindrical body rigidly mounted by internal thread with housing of the submersible motor; it contains low-voltage cosine capacitor fixed inside the module by a rubber gland. In upper and lower bases of the body of low-voltage cosine capacitor there are holes providing oil circulation inside hydroprotection system of the submersible motor in order to prevent the capacitor from impact of high formation pressure. Contacts of the cosine capacitor are in direct contact with oil inside hydroprotection system of the submersible motor. The cosine capacitor is connected electrically to stator windings. During operation of the submersible motor the cosine capacitor generates reactive power and transmits it to stator windings thus compensating inductive component of power and increasing power factor of the submersible motor.

EFFECT: higher power factor.

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Description

The invention relates to the field of electrical engineering and can be used to drive a submersible electric pump for lifting liquids from oil wells.

In the oil and gas industry, among the rodless pumps, the most common are the installation of submersible electric centrifugal pumps (ESP).

During operation of the ESP, the unit power factor is 0.7-0.8, depending on the calculated flow rate of the well and the correspondingly selected pump size. When the asynchronous electric motor is underloaded, the power factor decreases, and the larger the reactive component of the power, the more the loss of active power for its transmission.

It is known that submersible asynchronous three-phase electric motors (PEM) are used as a drive to the installations of electric centrifugal pumps that produce gas from wells. Control and protection of electric motors of submersible centrifugal pumps is carried out using a complex of equipment mounted in a control station.

One of the known methods for compensating reactive power losses is to install a low-voltage cosine capacitor as part of the equipment of the PED control station. But this arrangement of equipment has a significant drawback - the reactive power source is located at a large distance (1500-2000 m) from the consumer, that is, the submersible electric motor, which leads to an increase in reactive power losses along the length of the submersible cable supplying the SEM.

Known submersible electric motors [1] have a classic design and contain a cylindrical body with a stator with windings fixed to it, a rotor with a shaft, a current lead assembly, an engine hydraulic protection system.

The layout of the ESP with submersible electric motors in this design leads to a rather large loss of reactive power.

An object of the invention is the creation of a submersible motor with a high power factor.

The solution to this problem is achieved due to the maximum approximation of the reactive power source to the submersible motor by placing a low-voltage cosine capacitor inside the module connected to the SEM.

The inventive step of the proposed technical solution is that as a result of placing the capacitor in a module rigidly connected to a submersible electric motor, active power losses along the length of the submersible cable will be reduced, which in turn will provide an increase in the power factor of the SEM by reducing the loss of reactive power.

For example, with compensation of 20 kvar of reactive power of a well consuming 70 kW, the reduction in losses in the line with a voltage of 6 kV is 13%, with a distance of 3.5 km from the substation.

The proposed device is illustrated in figure 1 and is as follows.

A submersible electric motor with a high power factor consists of a housing 6 with a stator, a rotor, a current lead assembly, a hydraulic protection system (not shown), and a module connected to it. The module is a cylindrical housing 2, rigidly connected by an internal thread 5 to the housing of the submersible motor 6 and containing the housing of the low-voltage cosine capacitor 1, fixed inside this module by a rubber sleeve 4. In the upper and lower bases of the housing of the low-voltage cosine capacitor 1, openings 7 are provided that provide circulation of oil of the hydraulic protection system of the SEM in order to protect the capacitor from the effects of high reservoir pressure. The contacts of the 8 cosine capacitor are in direct contact with the oil of the PED hydraulic protection system. An electrically cosine capacitor is connected to the stator windings.

This device operates as follows.

When starting the PEM, voltage is applied to the stator windings, which is transmitted to the contacts of the low-voltage cosine capacitor. Under the action of voltage, the cosine capacitor generates reactive power and gives it to the stator windings, thereby compensating for the reactive component of the power and increasing the power factor of the SEM.

On average, the effect on one well from the introduction of a cosine capacitor with a capacity of 20 kvar is 1900 kWh per year.

List of used information sources.

1. "Downhole pumping units for oil production." V.N. Ivanovsky, V.I. Darishchev, A.A.Sabirov, V.S. Kashtanov, S.S. Pekin. "Oil and gas". M., 2002, pp. 113-137.

Claims (1)

A submersible electric motor containing a housing with a stator, rotor, current lead assembly, and a hydraulic protection system, characterized in that it further comprises a module rigidly attached to it by means of an internal thread, including a low-voltage cosine capacitor fixed inside the module by a rubber sleeve, and the capacitor hydraulically communicates with the submersible motor using through holes made in the upper and lower bases of the capacitor housing.

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