Overview
The appearance of the frequency conversion governor brought a revolution to AC speed regulation. With the continuous improvement and development of frequency conversion technology in recent decades. The frequency conversion speed regulation performance is perfect day by day, has already been applied to the alternating current velocity modulation in different fields by the engineering and technical personnel of different disciplines, different trades extensively. Brought considerable economic benefits to the company and promoted the automation of industrial production.
The frequency conversion speed regulation is used for the speed regulation of the AC asynchronous motor, and its performance far exceeds any AC and DC speed adjustment methods in the past. And the structure is simple, wide speed range, high speed accuracy, easy installation and commissioning, perfect protection function, stable and reliable operation, significant energy saving effect, has become the latest trend of AC motor speed. The common shared AC bus double loop solution is that the submersible pump is used outdoors (sea), its working environment and the working environment of its distribution equipment are all rather harsh; while the oil production operation requires high reliability of the oil extraction equipment, so In the actual use of the common AC bus frequency conversion system, an additional frequency standby system (inverter-frequency double-loop system) should be added, or a frequency conversion system should be installed on the basis of the original power frequency system so that the power frequency system and the frequency conversion system can be used as backups. Even if the frequency conversion system is in the state of failure or overhaul, the impact on the oil production is not great, so the safety and reliability of the oil extraction equipment (system) is improved.
Common DC bus double circuit system diagram
First, equipment selection:
1, in addition to the specified accessories, all imported devices
2. Each well uses a frequency converter and is equipped with an industrial frequency circuit to make an integrated frequency conversion cabinet.
Inverter specifications: The input voltage is: 3AC 1140V+15%, output power 55KW.
Second, power supply mode:
Transformer-rectifier power supply dual circuit wiring:
In order to ensure the safety and reliability of the system, ensure the normal operation and production of other wells in the event of failure of the frequency converter or rectifier or maintenance. This control system adopts the frequency conversion-power frequency dual-circuit connection method, and it is installed on the basis of retaining the original power frequency system. Frequency conversion system, the specific approach shown in Figure 3.
Explanation:
1. The capacity of the transformer is 1.3 times the sum of the capacity of all submersible electric pump motors.
2. The common AC bus voltage is: 1140VAC
3. The capacity of the inverter is the same as or slightly larger than the motor capacity of the boring machine.
4. Ensure that the phase sequence of power frequency and frequency conversion is consistent.
The optimal control of twitching parameters and the principle of power saving and efficiency increase Due to the different regions, different wells, well depths, oil levels, and oil viscosity differences, submersible pumps are required to have different reasonable twitch parameters. Usually, when the parameters of the submersible electric pump are fixed, the frequency (motor rotation speed or transmission ratio) can be adjusted by adjusting the frequency. This will not only save power and achieve the best economic benefits, but also the motor can start with zero current. Comprehensive protection.
Because the submersible pump is a variable load type, that is, the motor needs a large torque when starting, and the load is heavy when it is stopped. The motor is in the discharge state of the electric (magnetic) energy. The soft stop has a significant effect on preventing the oil from rushing down and the oil pump will not be damaged.
The initial investment of investment and energy-saving frequency conversion system is easy for investors to feel a sense of high investment risk. This is mainly due to the fact that the frequency conversion energy-saving effect is not well understood or the initial investment of the variable frequency system and some traditional speed-control methods, such as: hydraulic power The initial investment of speed control devices such as clutching, sliding-fork motor, variable speed control, etc. is not fully considered under the condition of energy saving effect and inverter function, and the quality, stability, after-sales service, etc. of the inverter are not quite enough. Understand the feeling; frequency conversion energy-saving system (device) when used in various types of speed control system, its energy-saving effect for a single device can be achieved 15-75%, in the absence of other factors, the general ceiling can be taken; energy-saving The average value of the effect is obtained by the actual application. The authoritative data can be found in the materials (books) that are publicly sold on the market; through the calculation of some simple investment returns, the data can be known; the investment recovery of the frequency conversion energy saving system (device) The period is usually 4-20 months (this is the empirical value and authoritative data).
Shenzhen Yingweiteng Electric Co., Ltd. produces 660V to 1140V voltage rated medium voltage drives at the same time according to the different needs of the oilfield oil production plant. Stand-alone capacity of 37KW ~ 630KW for users to choose, especially for deep wells more than 1300M deep wells in the use of electric submersible pumps.
The product is easy to install and use, and has perfect protection functions, especially the under-current protection (light-load automatic shutdown) and over-current protection (automatic shut-off due to silt, stones blocking the oil pump or other mechanical failure overload). To avoid and reduce the damage to the motor caused by idling and pumping the card, and to stop the production and maintenance of the great loss, which is welcomed by users.
Because the medium voltage inverter has the characteristics of adjustable output frequency, the user can adjust the speed of the electric submersible pump motor in time and conveniently according to the oil production volume and the change of the oil level, which is beneficial to stable production of the oil well and the energy saving rate can reach 30- 60%, high overall economic efficiency.
The application of variable-frequency energy-saving systems and production process automation systems in various industries in electromechanical equipment and production lines is an inevitable trend in the development of social production. It has the characteristics of early use, early reconstruction, early benefit, and rapid development, and it will be continuously applied. It will add brilliance to the development of enterprises and undertakings and will contribute to the development of the entire society.
Comprehensive Benefits The oil well submersible pump is a kind of large inertia changing load. The driving equipment used is a three-phase asynchronous motor, which has the disadvantages of low efficiency, inconvenient speed regulation, uncontrollable up and down stroke, and low power factor. In response to the above problems, our company has developed invt series products and common DC bus technology, and adopted advanced control methods to control the operation of submersible electric pumps to achieve the effect of energy saving, efficiency improvement, and production increase, while achieving the purpose of grid optimization. , Widely used in various domestic oil fields. Basic principle of energy-saving efficiency The control device is developed based on the principle of variable frequency speed control. Under the condition that the submersible pump has large inertia and variable load, this control device has the following features to achieve energy-saving effect.
→Speed-advanced energy-saving submersible electric pump is a sub-pump load, and its power consumption is PâˆN3. If the adjustment speed N satisfies the best stroke and up and down stroke speed, the power saving effect is amazing.
→Dynamic power adjustment function Under the working status of the submersible electric pump with variable load, the control device adapts the load of the motor at a speed of 7000 times per second, and automatically changes the terminal voltage applied to the motor to ensure that the motor is at the minimum current and the minimum voltage. That is, the operation is performed at the minimum power state, and the energy-saving effect is achieved, that is, energy is saved when the speed is not adjusted.
→Dynamic power factor compensation function The control device has power factor compensation function, which can replace the original control cabinet starter and compensator, make the system tend to integrate, ensure the motor power factor COS ∮> 0.95 or more, thereby reducing the equipment loss. Reduced line losses, transformed the power grid, increased installed capacity, and achieved energy savings.
→ Soft start function As the motor starts at full voltage, the starting current is equal to 3 to 7 times the rated current, so when the on-load motor starts up, it will cause serious impact on the motor and the power supply network, resulting in excessively high requirements on the power grid capacity. In addition, the large current and vibration generated on the device during start-up are extremely unfavorable to the device; the soft-start function of the control device will make the starting current much lower than the rated current, realizing the soft start of the motor and achieving the purpose of energy saving. . Not only reduces the impact on the power grid, but also can extend equipment life and maintenance cycle, reduce equipment maintenance costs.
→ The control device can arbitrarily set the speed of the submersible pump to meet the change of the crude oil level in the oil well. So that submersible pumps work in the best operating conditions at any time, to increase production and efficiency.