Application of Fuji Inverter in Oilfield

Application of Fuji frequency converter in oil field Abstract: This paper introduces the application of Fuji frequency converter series for constant pressure water supply in oil field

1. Inverter selection

Shengli Oilfield is located in Shandong Province. Because it is far away from cities, the transmission cost is high, and the average electricity price per kilowatt hour is more than 1 yuan, so it is very important for the oilfield to save electric energy to reduce oil production costs

in the operation area of Shengli Oilfield, the original water injection pump motor was controlled by an auto coupling step-down starter. After the starting impulse current was large and the operation was stable, the water injection pump worked at power frequency 24 hours a day for a long time, and the pressure was adjusted by the valve, wasting a lot of electric energy. In order to stop the waste of electric energy, on the basis of in-depth understanding of the energy-saving characteristics of the frequency converter, the person in charge of the oil field operation area decided to install a transformer for the water injection pump

through a large number of comparisons and screening, the oil field finally selected Fuji P11 series constant pressure water supply special inverter. The converter absorbs the advantages of various brands of converters in design, and adopts the world's advanced power module internally. The control circuit and the whole machine operate reliably. The input voltage range allows 20% of the rated voltage to fluctuate up and down, which is suitable for places with fluctuating voltage such as oil fields; The frequency converter is equipped with a built-in PI regulator, so that the water injection pump can easily form a closed-loop system; The price is lower than that of imported brands, but the performance is not lower than that of imported products, with good cost performance

2. Selection of scheme

there are three vertical water injection pumps of the same model in the operation area of Shengli Oilfield, which are placed in parallel, two for use and one for standby. The motor has a rated power of 75kW, a rated voltage of 380V, a rated current of 138A, a rated speed of 2900 rpm, a rated frequency of 50Hz, and an insulation grade of F. For two water injection pumps working and one standby, there is a problem of using one frequency converter or two frequency converters when using frequency converter speed regulation for constant pressure water supply:

2.1 power saving effect of using one frequency converter

this is a widely used scheme, and its control process is: when the water consumption is small, the frequency converter controls the No. 1 pump, Carry out constant pressure water supply control. When the water consumption gradually increases, and the working frequency of No. 1 pump reaches nearly 50Hz, switch its motor to power frequency power supply. At the same time, switch the frequency converter to No. 2 pump, and the No. 2 pump will supplement the water supply. On the contrary, when the water consumption gradually decreases, even if the working frequency of No. 2 pump has been reduced to the lower limit frequency, and the water supply pressure is still too high, turn off No. 1 pump, At the same time, the working frequency of No. 2 pump is rapidly increased and constant pressure control is carried out. The main feature of this scheme is that only one frequency converter is used, so the equipment investment is less. However, if the water consumption is just the same, the sample material can be divided into metal and non-metal. Coincidentally, if the water supply volume of one pump changes up and down at full speed, the water supply system will switch back and forth. In order to avoid this phenomenon, the water supply pressure can be set to a range. This method is suitable for occasions where the control accuracy is not very high. The calculation of electric power used in this scheme is as follows:

the capacity of the 75kW drive motor is pmn=75kw,

the water supply at full speed is QN

the no-load loss of the pump is po=0.1*75kw=7.5kw

the average total water supply flow per day is 140% Qn

then the No. 1 pump is at full speed, and its average intake power is pm2=pmn=75kw

while the average intake power of No. 2 is 40% of the average speed, and its average intake power is pm2= (7.5+0.43*75) kw=12.3kw

the total average power of the two pumps is 75+12.3=87.3

2.2 the power saving effect of using two frequency converters

using two frequency converters to control two motors respectively, the investment cost of primary equipment is high, but the energy-saving effect during operation.How? The calculation is as follows: the average total daily water supply flow is also 140% QN, and the water supply flow can be shared equally by two pumps, so the average water supply flow of each pump is 70% QN. The power of each motor is pm1= (7.5+0.73*75) kw=33.23kw. The common power of two water pumps is 2*33.23=66.46

from the above data, it can be seen that using two frequency converters saves 20.84kw more than using one frequency converter. Finally, it is decided to adopt the speed regulation scheme of two frequency converters

3. Electrical design

after the brand and quantity of frequency converter are selected, the circuit diagram is designed according to the user's requirements. The user requires the two frequency converters of the system to control the No.1 and No.2 water injection pumps and the No.3 water injection pump as the standby pump in a closed loop, and use the soft start control to start and stop. If the water injection pump in normal operation encounters fault or maintenance, it is estimated that the fault can be eliminated or the maintenance can be completed within one day. During this period, the standby pump can be started. The pressure of the water injection pump on the secondary control line is given by the K potential, The pressure feedback value is formed by the pressure transmitter with ma current and input from the is end. The start and stop of the frequency converter is a three wire operation mode composed of FWD, X1 and com terminals, and it is a logical start and stop of duplex control. PM and GND connect V DC, which has high operation speed and data processing ability. Voltmeter is used to observe the output frequency of frequency converter. A and C are connected to flash alarm, which will alarm in time in case of frequency converter failure. Primary main 2 Rubber tensile testing machine: the 380V power supply of the line with large rubber or elastomer elongation is connected to the R, s and t terminals of the frequency converter through the circuit breaker QF. U, V and W are the output of the frequency converter and connected to the water injection pump motor. When connecting, be sure not to connect the incoming and outgoing power supplies reversely

4. Main parameter setting and debugging

h03=1 restore the factory setting value

f01=3 analog current/voltage terminal (is-gnd) Zhongwang has the current input setting of all-round ability from independent design to manufacturing and processing vehicle aluminum, Range: dco-20ma

f02=2 control terminal control

f12 lower limit rate

p1 upper limit rate

f93=1 prohibit inverter reverse operation

f11=4 select the closed-loop control function of analog feedback

f90=2 given by VCI analog voltage

f91=3 Ma input by CCI analog current

f88 proportion

f89 integral

check and confirm that there is no error. Check again whether the motor line and control line are connected correctly, Power on and operate after confirmation. Due to the meticulous preliminary work, the trial run was successful

5. Conclusion

after half a year of operation, the frequency converter operates stably. The two water injection pumps generally operate at about 40Hz, and the energy-saving effect is very obvious. The investment was recovered within one year. The mechanical wear of the equipment was small, the noise was significantly reduced, the degree of automation was improved, the labor intensity was reduced, and the amount of electrical and mechanical maintenance was greatly reduced. Users were very satisfied