Petrochemical
SINCR C500 Inverter on Oilfield kowtow machineI. OverviewKowtow machine is the main oil production equipment, the number of 10 million units or more. Motor total installed capacity of 35 million kW, annual power consumption of more than ten billion degrees. Kowtow machine about 40% of the total electricity consumption of oil, operating efficiency is very low, only 25% of the average operating efficiency, low power factor, energy waste. Therefore, kowtow machine energy-saving potential is enormous, the oil industry is the promotion of "motor system energy saving" key industries. This article describes the use of frequency control technology, the movement of kowtow machine to adapt to changing conditions of the well, to achieve system efficiency to save energy yield purposes.II. several benefits pumping frequency transformation1, greatly improve the power factor, (0.25 to 0.5 up to 0.9 or more). It reduces the supply current, thereby reducing the load on the power grid and transformer.2, the dynamic adjustment of extraction rate, on the one hand energy saving, while increasing crude oil production.3, to achieve true "soft start" pumping motor gearbox, to avoid excessive mechanical impact, extended equipment life. III. kowtow machine load analysis1, the domestic most widely used is the beam shaft kowtow machine, it consists of three parts:(1) ground segment: consists of a motor, a speed reducer and a four-link.(2) underground parts: pump (suction valve, pump barrel, plunger and drain valve), which hung at the lower end of the sleeve.(3) sucker rod: connecting ground and underground drainage pumping an intermediate portion of the pump.2, the motor load kowtow machine is periodically change, starting at the beginning, a large load, requiring a large starting torque. Normal operation, the load rate is very low, usually around 20%, high load factor of only 30%. Motor load curve has two peaks, respectively, on kowtow machine, downstroke of "dead spots."No balance under the conditions of the upper and lower stroke load is extremely uneven, when the stroke, need to lift the rod string and the liquid column, the motor will have to pay a lot of energy. At the next stroke, sucker rod motor for power, the motor in the power generation state. Usually coupled with the crank balancer kowtow machine, eliminating the up and down strokes unbalanced load. Weights adjust better time its power status and the energy generated is small, due to the pumping load is changing all the time, with the balance weight can not exactly the same as the pumping load changes, most kowtow machine counterweight serious imbalance, resulting in an excessive inrush current, impulse current can be up to 5 times the operating current, even up to 3 times the rated current. Adjust the counterweight, can reduce the inrush current of 1.5 times the normal operating current.Load characteristics: a constant speed, due to the weight, it is variable torque, variable power load in a cycle twice the power generation state, starting torque, inertia. In domestic oil use kowtow machine common problem: a long running time, the "big horse car", low efficiency, energy consumption, stroke and stroke rate adjustment is not convenient, free pumping phenomenon. IV. the traditional kowtow machine frequency transformation DifficultiesKowtow machine frequency energy-saving a lot of attempts, but all with little success, the main question is:(1) kowtow machine in a working cycle, there are two power generation state, especially when the weight imbalance, resulting "pumping voltage" is high, by increasing the inverter DC side electrolytic capacitors and reduce the brake resistor value, can not completely solve the problem, and with the change of reservoir, "pumping voltage" is changing.(2) Starting kowtow machine requires a large starting torque, such as the inverter parameters are set incorrectly, it could easily lead to an overcurrent or not start.(3) frequency energy transformation conventional design with little regard for oil wells, changes in oil concentration and so on. In terms of improving yield poor results. V. SolutionFrequency transformation kowtow machine problems Division I propose the following solutions:(1) frequency control technology, the motor speed and load matching kowtow machine. Because just in the early exploration well, big oil, let the inverter run to 65.00Hz, motor speed increased by 30%, oil production rate increased by 20% than the frequency, efficiency increased 1.2 times. In the latter part of the well, reducing the amount of oil, reduce speed, reduce stroke, between the general frequency operation to 35.00 ~ 40.00Hz, the motor speed is decreased by 30%. Saving rate of 25%, and improve the power factor.(2) dynamic adjustment kowtow machine stroke and frequency, as well Deep extraction, oil gradually decreases, and there is full lack of pump, pump efficiency drops when the supply capacity of the well is less than pump displacement, causing evacuating pump and hydraulic shock phenomenon. Reduce the frequency, speed reduction, increase fullness, not only energy but also increase oil production.(3) dynamically adjust the speed kowtow machine up and down stroke, the speed appropriate to reduce the down stroke, increase fullness in the pump, an appropriate increase in the travel speed can be reduced to enhance the leakage coefficient, so kowtow machine work in the best running condition, effective increase crude oil production per unit time.(4) starting torque, low load operation, a large inrush current. Fundamentally solve the problem, increase the number of pole pairs of the motor or gearbox ratio is increased, increasing the output torque. Inverter running 80.00 ~ 90.00Hz. This also helps to reduce the power generation state of energy, reducing "pumping voltage."(5) deal with the issue of renewable energy. Increasing the inverter DC side filter ca...