CN102735382A - Energy efficiency test method and device of variable frequency oil pump unit - Google Patents

Abstract

The invention relates to a method and device for testing the energy efficiency of a frequency conversion oil pump unit, which calculates the efficiency of a frequency conversion oil pump; calculates the input power of a frequency conversion motor; calculates the output power of an oil pump under a frequency conversion condition; calculates the input power of an oil pump under a frequency conversion condition; The output power of the motor under the condition; calculate the efficiency of the frequency conversion motor; obtain the energy efficiency model of the frequency conversion oil pump unit through the efficiency of the frequency conversion oil pump and the efficiency of the frequency conversion motor to calculate the energy efficiency of the frequency conversion oil pump unit. Wherein, the calculation of the output power of the motor under the frequency conversion condition includes: ignoring the power loss in the transmission process, according to the principle of energy conservation, the power of the output shaft of the transmission mechanism is equal to the power of the input shaft, that is, the output power of the motor under the frequency conversion condition The power is equal to the input power of the oil delivery pump under the frequency conversion condition, and the output power of the motor under the frequency conversion condition is obtained through the input power of the oil delivery pump under the frequency conversion condition obtained in the calculation step of the input power of the oil delivery pump under the frequency conversion condition.

Description

A method and device for testing the energy efficiency of a variable frequency oil delivery pump unit

technical field

The invention relates to an oil delivery pump unit under variable frequency working conditions, in particular to a method for calculating the energy efficiency of a frequency conversion oil delivery pump unit based on the temperature difference between the pumps, and according to the operation data collected by the SCADA system of the current oil delivery station, combined with the existing energy-saving testing equipment, a quick and easy method is formulated. Simple energy efficiency testing scheme for frequency conversion oil pump unit.

Background technique

It is estimated that 20% to 50% of the electric energy consumed by industrial pumps can be saved by frequency conversion technology. The application of frequency conversion speed regulation technology in our country is only more than ten years. With the development of foreign frequency converters, the development of frequency conversion speed regulation technology in our country is also very rapid. In recent years, the economic benefits produced by frequency conversion speed regulation in various industries are superior to other speed regulation methods in the past, and it has become the center of the electric drive industry.

The energy efficiency calculation of the frequency conversion oil pump unit is an important content to measure the effect of frequency conversion, which reflects the operation status and energy utilization of the oil pump unit under the frequency conversion condition. Among them, the calculation of the output power of the motor under the frequency conversion condition is the key to the energy efficiency calculation of the entire frequency conversion oil pump unit. In the energy efficiency calculation of the current frequency conversion oil pump unit, the relevant energy efficiency calculation model is usually determined according to the characteristics of the square torque load of the pump and the equivalent principle of electromagnetic conversion inside the motor.

At present, the national petroleum industry has formulated and promulgated a series of related standards and specifications such as SY/T 6834-2011 "Energy Saving Test Methods and Evaluation Indexes for Variable Frequency Drive Drive Devices". According to the square torque load of the centrifugal pump, Meir et al. used the proportional law method to calculate the shaft power and efficiency of the oil pump under variable frequency conditions, and evaluated the energy-saving potential of the pump unit. During the calculation, the mechanical efficiency of the oil pump at different speeds was considered to be equal. The calculation result is not accurate enough. Metwally et al. (2002) based on the equivalent circuit of the motor, used the known basic parameters of the motor, calculated the output power of the motor based on the output torque of the motor, and then calculated the efficiency of the motor and the efficiency of the oil delivery pump, but the field test of the variable frequency oil delivery pump unit was rarely There are specific descriptions. Daut et al. (2009) calculated the efficiency of an asynchronous motor with a rated power of 5 horsepower, analyzed the situation of active power transfer from the T-type equivalent circuit of the motor, and calculated the motor efficiency by calculating the loss efficiency of the motor, but the parameters required in the calculation , such as motor stator, rotor phase resistance, leakage reactance and excitation reactance, etc., are difficult to obtain in the field test or estimated by experience, which makes the calculation limited. Zhang Yanbin et al. (2002) started from the electromagnetic induction conversion between the motor stator and rotor, performed dynamic and static conversion and magnetoelectric conversion for the complex operation process, and derived the formula for calculating the torque of the motor after frequency conversion from the equivalent circuit principle. In order to obtain the equivalent circuit of the asynchronous motor when the rotor is rotating, in order to simplify the analysis and calculation process, an equivalent stationary rotor is used to replace the original rotating rotor, so that the potential and current frequency in the equivalent rotor are the same as those of the stator. According to the equivalent principle, the corresponding parameters of the original rotation are converted, which is called frequency conversion. The parameters of the equivalent static rotor after frequency conversion are then converted to the stator side by converting the physical quantities on the rotor side to the stator side, and then the required equivalent circuit can be obtained. However, the parameters required for calculation, such as the resistance of each phase of the motor stator and rotor, the leakage reactance of each phase, etc., are difficult to obtain in the field test, which brings inconvenience to the actual test on site. Qiu Arui et al. (2002) analyzed the active power transfer according to the T-type equivalent circuit of the motor, and calculated the motor efficiency by calculating the motor power loss, but the parameters required for calculation, such as the resistance of each phase of the motor stator and rotor, and the leakage reactance of each phase And excitation reactance, etc., are also difficult to obtain or rely on experience to estimate in field tests, making calculations limited.

The energy efficiency calculation of variable frequency oil pump units at home and abroad can be roughly divided into three categories. One is to use the proportional law to calculate, the other is to directly deduce according to the principle of the equivalent circuit of the motor, and the third is to calculate the motor power loss efficiency and then calculate the motor efficiency. Using the above methods, the efficiency of the motor under variable frequency conditions can be calculated in theory, but it is difficult to obtain the required motor parameters in the actual test, or the calculation method results have large deviations, and it is difficult to realize and promote it in practical applications. If the torque meter is directly used to test the output torque of the motor, whether it is an invasive torque meter or a non-intrusive torque meter, torque sensing equipment must be installed when the unit is out of operation, and the invasive torque meter must also be installed between the motor shaft and the pump shaft It can only be used as a part of the shaft system, which brings inconvenience to the production site.

Therefore, it is necessary to study a new energy efficiency calculation method for variable frequency oil pump units, and to meet the actual needs of field tests on the basis of accurate calculations.

Contents of the invention

The purpose of the present invention is to address the problems and limitations of each method in the field test, combined with actual operation, deduce and establish the energy efficiency calculation method of the frequency conversion oil pump unit based on the temperature difference of the pump, according to the energy efficiency calculation method of the frequency conversion oil pump unit, determined The parameters needed to be measured for the energy efficiency test of the frequency conversion oil pump unit, its implementation standards and related instruments, and an operable energy efficiency test plan for the frequency conversion oil pump unit have been formulated.

In order to achieve the above purpose, the present invention provides a method for testing the energy efficiency of a variable frequency oil delivery pump unit, including:

Calculate the efficiency of the frequency conversion oil pump;

Calculate the input power of the variable frequency motor;

Calculate the output power of the oil transfer pump under the frequency conversion condition;

Calculate the input power of the oil pump under the frequency conversion condition through the output power of the oil pump under the frequency conversion condition;

Calculate the output power of the motor under the frequency conversion condition through the input power of the oil pump under the frequency conversion condition;

The efficiency of the variable frequency motor is calculated by the input power of the variable frequency motor and the output power of the motor under variable frequency conditions;

The energy efficiency of the frequency conversion oil pump unit is tested by the efficiency of the frequency conversion oil pump and the efficiency of the frequency conversion motor.

Optionally, in an embodiment of the present invention, the testing of the energy efficiency of the variable frequency oil pump unit through the efficiency of the variable frequency oil pump and the efficiency of the variable frequency motor includes:

According to the energy efficiency model of the frequency conversion oil pump unit, the field parameters required for the field test are determined;

Select instruments according to site parameters, and test the selected instruments;

According to the energy efficiency model of the variable frequency oil delivery pump unit, the motor and the oil delivery pump are tested to obtain the motor test parameters, the oil delivery pump test parameters, the motor test parameters under the frequency conversion condition, and the oil delivery pump test parameters under the frequency conversion condition;

Use the tested instruments to conduct on-site tests to obtain on-site parameters;

According to the motor test parameters, oil pump test parameters, field parameters, motor test parameters under variable frequency conditions and oil pump test parameters under variable frequency conditions, the energy efficiency model of the variable frequency oil pump unit is used for calculation to realize the energy efficiency test of the variable frequency oil pump unit.

Optionally, in an embodiment of the present invention, the calculation of the output power of the motor under variable frequency conditions includes:

Neglecting the power loss in the transmission process, according to the principle of energy conservation, the power of the output shaft of the transmission mechanism is equal to the power of the input shaft, that is, the output power of the motor under the condition of frequency conversion is equal to the input power of the oil pump under the condition of frequency conversion. The output power of the motor under the frequency conversion condition is obtained from the input power of the oil delivery pump under the frequency conversion condition obtained in the calculation steps of the input power of the oil delivery pump under the frequency conversion condition.

Optionally, in an embodiment of the present invention, the calculating the input power of the variable frequency motor includes:

The parameters required for calculating the input power of the variable frequency motor are measured, and the input power of the variable frequency motor is calculated according to the parameters.

Optionally, in an embodiment of the present invention, the method for measuring the parameters required for calculating the input power of the variable frequency motor is the electric energy meter method.

Optionally, in an embodiment of the present invention, the method for measuring the parameters required for calculating the input power of the variable frequency motor is the current voltage power factor method.

Optionally, in an embodiment of the present invention, the instrument includes: a power analyzer, a float density meter, a viscometer, a hand-held laser tachometer, a portable flow meter, and a mercury-in-glass thermometer.

Optionally, in an embodiment of the present invention, the test parameters of the oil transfer pump include inlet crude oil temperature, outlet crude oil temperature, inlet crude oil pressure, outlet crude oil pressure, crude oil density and measured crude oil volume flow rate.

Optionally, in an embodiment of the present invention, the test parameters of the oil delivery pump under variable frequency working conditions include inlet and outlet temperature, pressure and volume flow.

In order to achieve the above purpose, the present invention also provides an energy efficiency testing device for a variable frequency oil delivery pump unit, including:

The frequency conversion oil pump efficiency unit is used to calculate the efficiency of the frequency conversion oil pump;

The variable frequency motor input power unit is used to calculate the input power of the variable frequency motor;

The output power unit of the oil delivery pump under the frequency conversion condition is used to calculate the output power of the oil delivery pump under the frequency conversion condition;

The input power unit of the oil delivery pump under the frequency conversion condition is used to calculate the input power of the oil delivery pump under the frequency conversion condition through the output power of the oil delivery pump under the frequency conversion condition;

Motor output power unit under frequency conversion condition, which is used to calculate the output power of motor under frequency conversion condition through the input power of oil pump under frequency conversion condition;

The variable frequency motor efficiency unit is used to calculate the variable frequency motor efficiency through the input power of the variable frequency motor and the output power of the motor under the variable frequency working condition;

The energy efficiency test unit of the frequency conversion oil pump unit is used to test the energy efficiency of the frequency conversion oil pump unit through the efficiency of the frequency conversion oil pump and the efficiency of the frequency conversion motor.

Optionally, in an embodiment of the present invention, the energy efficiency test unit of the frequency conversion oil delivery pump unit includes:

The on-site parameter determination module is used to determine the on-site parameters required for on-site testing according to the energy efficiency model of the variable frequency oil delivery pump unit;

The instrument test module is used to select instruments according to field parameters and test the selected instruments;

The test parameter acquisition module is used to obtain the motor test parameters, the oil pump test parameters, the motor test parameters under the frequency conversion condition, and the oil delivery pump test parameters under the frequency conversion condition through testing the motor and the oil delivery pump according to the energy efficiency model of the frequency conversion oil delivery pump unit;

The on-site parameter acquisition module is used to use the tested instrument to perform on-site testing to obtain on-site parameters;

The energy efficiency acquisition module is used to calculate by using the energy efficiency model of the variable frequency oil pump unit according to the motor test parameters, the oil pump test parameters, the field parameters, the motor test parameters under variable frequency conditions, and the oil pump test parameters under variable frequency conditions to realize the variable frequency oil pump Unit energy efficiency test.

Optionally, in an embodiment of the present invention, the calculation of the output power of the motor under variable frequency conditions by the motor output power unit under variable frequency conditions includes:

Neglecting the power loss in the transmission process, according to the principle of energy conservation, the power of the output shaft of the transmission mechanism is equal to the power of the input shaft, that is, the output power of the motor under the condition of frequency conversion is equal to the input power of the oil pump under the condition of frequency conversion. The output power of the motor under the frequency conversion condition is obtained from the input power of the oil delivery pump under the frequency conversion condition obtained in the calculation steps of the input power of the oil delivery pump under the frequency conversion condition.

Optionally, in an embodiment of the present invention, the calculation of the input power of the variable frequency motor by the variable frequency motor input power unit includes:

The parameters required for calculating the input power of the variable frequency motor are measured, and the input power of the variable frequency motor is calculated according to the parameters.

Optionally, in an embodiment of the present invention, the selected instruments of the instrument testing module include: power analyzers, float density meters, viscometers, hand-held laser tachometers, portable flow meters and glass mercury thermometers.

Optionally, in an embodiment of the present invention, the test parameters of the oil transfer pump acquired by the test parameter acquisition module include inlet crude oil temperature, outlet crude oil temperature, inlet crude oil pressure, outlet crude oil pressure, crude oil density and measured crude oil volume flow.

The above technical scheme has the following beneficial effects: By comparing the energy efficiency calculation methods at home and abroad in this field under the frequency conversion condition, aiming at the problems and limitations of each method in the field test, combined with the actual operation, the calculation method based on the temperature difference of the pump is deduced and established. The energy efficiency calculation method of the frequency conversion oil pump unit requires fewer calculation parameters and the calculation process is simple, which brings convenience to the actual test on site. According to the calculation method of the energy efficiency of the frequency conversion oil pump unit, the parameters to be measured for the energy efficiency test of the frequency conversion oil pump unit, its execution standards and related instruments are determined, and an operable energy efficiency test plan for the frequency conversion oil pump unit is formulated.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is one of the flow charts of a method for testing the energy efficiency of a variable frequency oil delivery pump unit proposed by the present invention;

Fig. 2 is the second flow chart of a method for testing the energy efficiency of a variable frequency oil delivery pump unit proposed by the present invention;

Fig. 3 is a block diagram of an energy efficiency testing device for a variable frequency oil delivery pump unit proposed by the present invention;

Fig. 4 is a block diagram of the composition of the energy efficiency test unit of the frequency conversion oil pump unit in the energy efficiency test device of the frequency conversion oil pump unit proposed by the present invention;

Fig. 5 is a schematic diagram of the arrangement of the temperature measuring points and the pressure measuring points of the oil transfer pump in a method for testing the energy efficiency of the frequency conversion oil transfer pump unit proposed by the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

When calculating the energy efficiency of the frequency conversion oil pump unit, it is difficult to directly test and calculate the output power of the motor. In the case that the motor speed decreases a lot, the shaft power of the oil delivery pump is calculated by the proportional law method, and the result is smaller than the actual value under the same conditions. The output power of the motor is calculated according to the motor torque calculation formula or the motor loss power formula. Under the current field conditions, the required motor parameters such as the leakage reactance of each phase of the stator and rotor are difficult to measure, so it cannot be calculated. By comparing the energy efficiency calculation methods at home and abroad in this field under frequency conversion conditions, aiming at the problems and limitations of each method in the field test, combined with actual operation, the energy efficiency calculation method of frequency conversion oil pump unit based on the temperature difference of the pump is deduced and established. And according to the energy efficiency calculation method of the frequency conversion oil pump unit, the parameters that need to be measured for the energy efficiency test of the frequency conversion oil pump unit, its execution standards and related instruments are determined, and an operable energy efficiency test plan for the frequency conversion oil pump unit is formulated.

This application includes two parts: the efficiency calculation model of the frequency conversion oil pump unit and the energy efficiency test plan of the frequency conversion oil pump unit.

As shown in FIG. 1 , it is one of the flow charts of a method for testing the energy efficiency of a variable frequency oil delivery pump unit proposed by the present invention. The method includes:

Step 101: Calculate the efficiency of the variable frequency oil delivery pump;

Step 102: Calculate the input power of the variable frequency motor;

Step 103: Calculate the output power of the oil transfer pump under the frequency conversion condition;

Step 104: Calculate the input power of the oil delivery pump under the frequency conversion condition according to the output power of the oil delivery pump under the frequency conversion condition;

Step 105: Calculate the output power of the motor under the frequency conversion condition according to the input power of the oil pump under the frequency conversion condition;

Step 106: Calculate the efficiency of the variable frequency motor according to the input power of the variable frequency motor and the output power of the motor under the variable frequency working condition;

Step 107: Test the energy efficiency of the variable frequency oil pump unit through the efficiency of the variable frequency oil pump and the efficiency of the variable frequency motor.

As shown in FIG. 2 , it is the second flow chart of a method for testing the energy efficiency of a variable frequency oil delivery pump unit proposed by the present invention. Further, change step 105 to step 105': Neglect the power loss in the transmission process, according to the principle of energy conservation, the power of the output shaft of the transmission mechanism is equal to the power of the input shaft, that is, the output power of the motor under the frequency conversion condition is equal to The input power of the oil delivery pump under the frequency conversion condition is equal, and the output power of the motor under the frequency conversion condition is obtained through the input power of the oil delivery pump under the frequency conversion condition obtained in the calculation step of the input power of the oil delivery pump under the frequency conversion condition. Then, a method for calculating the energy efficiency of the frequency conversion oil pump unit proposed by the present invention is based on the energy conversion relationship of the frequency conversion oil pump unit and divides each research unit according to the black box principle to study its energy balance. Combined with the actual test and calculation on site, the over-pump temperature difference method is proposed. This method is based on the principle of thermodynamic energy conservation and conversion, and analyzes the temperature rise generated when crude oil flows through the oil pump. The enthalpy difference at the inlet and outlet of the oil delivery pump is equivalent to the sum of the constant entropy enthalpy difference and the constant pressure enthalpy difference, and the calculation of the efficiency of the oil delivery pump under the frequency conversion condition is derived.

Wherein, step 101: Calculate the efficiency of the frequency conversion oil delivery pump according to formula (1).

${\mathrm{<span\; class="notranslate">\; \&eta;</span>}}_{\mathrm{<span\; class="notranslate">\; VF</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; pe</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; h</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 102</span>}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Delta;P</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

为输油泵所输送原油的平均比定压热容，J/(kg·K)。In the formula: η _{VF, pe} is the efficiency of the oil delivery pump under variable frequency conditions, %; H is the lift of the oil delivery pump, m; Δt is the temperature difference between the inlet and outlet of the oil delivery pump, K; ΔP is the pressure difference between the inlet and outlet of the oil delivery pump, _MPa ; Temperature rise coefficient of isentropic compression of crude oil transported, °C/Mpa;

It is the average heat capacity at constant pressure of the crude oil transported by the oil pump, J/(kg·K).

Step 102: Measure the parameters required to calculate the input power of the variable frequency motor. For those skilled in the art, there are many measurement methods, preferably the electric energy meter method and the current voltage power factor method.

① Energy meter method

Measure the time t required for the rotation of the electric energy meter, the transformation ratio K _i of the electric energy meter and the transformation ratio _{Ku of} the electric energy meter, and calculate the input power of the variable frequency motor according to formula (2).

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; VF</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; mi</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 10</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 3600</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

In the formula: K is the actual constant of the electric energy meter, r/(kW h); t is the time required for the electric energy meter to turn 10 revolutions, s; K _i is the transformation ratio of the electric energy meter; K _u is the transformation ratio of the electric energy meter. Calculate the input power of the variable frequency motor according to the parameters.

②Current voltage power factor method

以上参数可通过输油站电力SCADA系统获得，或者用电力分析仪测得。根据式（3）计算获得变频电动机输入功率。Measure the motor input terminal line voltage U _{VF, lmi under} the frequency conversion condition, the motor input terminal line current I _{VF, lmi under} the frequency conversion condition and the power factor of the motor at the operating frequency under the frequency conversion condition

The above parameters can be obtained through the power SCADA system of the oil station, or measured with a power analyzer. Calculate the input power of the variable frequency motor according to formula (3).

为变频工况下电动机在运行频率下的功率因数。In the formula: U _VF,lmi is the input terminal line voltage of the motor under the frequency conversion condition, kV; _IVF,lmi is the input terminal line current of the motor under the frequency conversion condition, A;

It is the power factor of the motor at the operating frequency under the condition of variable frequency.

Step 103: Calculate the output power of the oil transfer pump under the frequency conversion condition according to formula (4)

P _{VF, po} = ρgHQ×10 ^-3 (4)

In the formula, ρ is the density of the crude oil being transported, kg/m ³ ; H is the head obtained when the crude oil being transported flows through the oil pump, m; Q is the volume flow rate of the crude oil being transported, m ³ /s.

Step 104: Calculate the input power of the oil transfer pump under the frequency conversion condition according to the formula (5) according to the output power of the oil transfer pump under the frequency conversion condition

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; VF</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; VF</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; po</span>}}}{{\mathrm{<span\; class="notranslate">\; \&eta;</span>}}_{\mathrm{<span\; class="notranslate">\; VF</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; pe</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

In the formula, P _{VF, po} is the output power of the oil transfer pump under the frequency conversion condition, kW.

Step 105: Calculate and obtain the output power of the motor under variable frequency conditions; furthermore, the on-site transmission mechanism follows the principle of energy conservation in the process of transmitting the torque and speed on the motor shaft under variable frequency conditions to the oil delivery pump, that is, if the transmission process The power loss in is negligible, then the power of the output shaft of the transmission mechanism is equal to the power of the input shaft, that is, the output power of the motor P _{VF, mo} is equal to the shaft power of the centrifugal pump P _{VF, pi} under the condition of frequency conversion.

P _{VF, pi} = P _{VF, mo} (6)

In the formula, P _{VF, pi} is the input power of the oil pump under the variable frequency condition, kW; P _{VF, mo} is the output power of the motor under the variable frequency condition, kW.

Step 106: Calculate the efficiency of the variable frequency motor according to the formula (7) according to the input power of the variable frequency motor and the output power of the motor under the variable frequency working condition.

${\mathrm{<span\; class="notranslate">\; \&eta;</span>}}_{\mathrm{<span\; class="notranslate">\; VF</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; me</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; VF</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; mo</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; VF</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; mi</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

In the formula: η _VF,me is the efficiency of the motor under variable frequency conditions, %; P _VF,mo is the output power of the motor under variable frequency conditions, kW; P _VF,mi is the input power of the motor under variable frequency conditions, kW.

Step 107: Calculate the energy efficiency of the frequency conversion oil pump unit by obtaining the energy efficiency model of the frequency conversion oil pump unit in formula (8) through the frequency conversion oil pump efficiency and the frequency conversion motor efficiency.

η _VF ＝η _VF,me η _VF,pe (8)

In the formula, η _VF is the efficiency of the oil delivery pump unit under the frequency conversion condition, %.

As shown in FIG. 3 , it is a block diagram of an energy efficiency testing device for a variable frequency oil delivery pump unit proposed by the present invention. include:

The frequency conversion oil pump efficiency unit 31 is used to calculate the frequency conversion oil pump efficiency;

The variable frequency motor input power unit 32 is used to calculate the variable frequency motor input power;

The output power unit 33 of the oil delivery pump under frequency conversion conditions is used to calculate the output power of the oil delivery pump under frequency conversion conditions;

The input power unit 34 of the oil delivery pump under the frequency conversion condition is used to calculate the input power of the oil delivery pump under the frequency conversion condition according to the output power of the oil delivery pump under the frequency conversion condition;

The motor output power unit 35 under the frequency conversion condition is used to calculate the output power of the motor under the frequency conversion condition through the input power of the oil pump under the frequency conversion condition;

The variable frequency motor efficiency unit 36 is used to calculate the variable frequency motor efficiency through the input power of the variable frequency motor and the output power of the motor under the variable frequency working condition;

The energy efficiency testing unit 37 of the frequency conversion oil pump unit tests the energy efficiency of the frequency conversion oil pump unit through the efficiency of the frequency conversion oil pump and the efficiency of the frequency conversion motor.

As shown in FIG. 4 , it is a block diagram of the composition of the energy efficiency test unit of the frequency conversion oil pump unit in the energy efficiency test device of the frequency conversion oil pump unit proposed by the present invention. The energy efficiency test unit 37 of the frequency conversion oil pump unit includes:

The on-site parameter determination module 41 is used to determine the on-site parameters required for the on-site test according to the energy efficiency model of the variable frequency oil delivery pump unit;

The instrument testing module 42 is used to select an instrument according to field parameters, and to test the selected instrument;

Among them, the test instruments include power analyzer, float density meter, VT500 viscometer, CT6LSR hand-held laser tachometer, FLUXUS F601 portable flow meter and glass mercury thermometer, etc. The power analyzer is preferably HIOKI 3166 power analyzer, the viscometer is preferably VT500 viscometer, the laser tachometer is preferably CT6LSR handheld laser tachometer, and the portable flow meter is preferably FLUXUS F601 portable flow meter.

The accuracy of the test instrument should meet: the accuracy level of current should not be lower than 1.0; the accuracy level of voltage should not be lower than 1.0; the accuracy level of power factor should not be lower than 1.0; the accuracy of active power The grade should not be lower than 1.0; the accuracy of frequency should not be lower than 1.0; the accuracy of voltage harmonic test should meet the requirements of D5.3 in GB/T 14549; When installing, the supporting voltage and current transmission equipment should have good frequency characteristics, the amplitude error introduced by it should not be greater than 5%, and the phase angle error should not be greater than 5°.

The test parameter acquisition module 43 is used to obtain the motor test parameters, the oil pump test parameters, the motor test parameters under the frequency conversion condition, and the oil delivery pump test parameters under the frequency conversion condition through testing the motor and the oil delivery pump according to the energy efficiency model of the frequency conversion oil delivery pump unit;

Among them, the motor test parameters include: input line voltage U _{VF, lmi} , V, input line current I _{VF, lmi} , A; power factor, Or input power P _{VF, mi} , kW.

The test parameters of the oil pump include: inlet crude oil temperature T _{VF, 1} , ℃; outlet crude oil temperature T _{VF, 2} , ℃; inlet crude oil pressure P _VF,pi , MPa; outlet crude oil pressure P _{VF, po} , MPa; Density ρ ²⁰ , kg/m ³ ; measured crude oil volume flow rate Q, m ³ /h.

Parameter testing is mainly based on standards: GB/T 1884-2000 "Laboratory Determination of Density of Crude Oil and Liquid Petroleum Products (Densitometer Method)"; SY/T 0520-2008 "Rotational Viscometer Balance Method for Determination of Crude Viscosity"; JB/T 10391-2002 "Standards of the Machinery Industry of the People's Republic of China"; GB/T 1032-2005 "Test Methods for Three-phase Asynchronous Motors"; and energy-saving detection method of liquid delivery system".

On the oil delivery station installed with SCADA system, if the instruments in the station meet the accuracy and are within the maintenance period, then according to the data collected by the SCADA system in the station, the required process parameters, such as power parameters, etc. are read from the control room. If the SCADA system is not installed at the oil station, or the SCADA system is installed but cannot meet the required parameter measurement requirements, such as insufficient instrument accuracy, instrument damage, or relevant instruments for measuring the required test parameters are not installed, etc., you need to use the built-in instrumentation The equipment is tested on-site or taken to the laboratory for analysis and testing after sampling.

Motor parameters under variable frequency conditions include voltage, current and power factor. Method of measuring current, voltage and power factor: In a station with real-time collection and display of power parameters, go to the power supply and distribution room in the station to read the power parameters. For stations that do not have real-time acquisition and display of power parameters, use the HIOKI 3166 power analyzer produced by Japan's HIOKI EE Company to test the site on the wiring terminals of the power distribution cabinet of the oil pump unit, and read the value of the motor input power P _mi .

The parameters of the oil delivery pump under the condition of frequency conversion include inlet and outlet temperature, volume flow and pressure. When conducting the temperature difference method test of the oil pump unit, first add heat transfer oil to the temperature measuring sleeve at the inlet and outlet of the oil transfer pump, so that the precision thermometer used for testing is fully immersed in the heat transfer oil to ensure the accuracy of temperature measurement at the inlet and outlet of the oil transfer pump .

The temperature measurement point and pressure measurement point should be in the fully developed section of the oil flow in and out of the oil pump, according to the provisions of GB/T 33216-1989 "Centrifugal Pumps, Mixed Flow Pumps, Axial Flow Pumps and Vortex Pumps", as shown in Figure 5 , which is a schematic diagram of the arrangement of temperature measurement points and pressure measurement points of the oil transfer pump in a method for testing the energy efficiency of the frequency conversion oil transfer pump unit proposed by the present invention. The distance between the temperature measuring point at the inlet of the oil pump and the flange before the inlet of the oil pump is greater than or equal to 3 times the inlet diameter D1, the distance between the pressure measuring point and the flange before the inlet of the oil pump is greater than or equal to 2 times the inlet diameter D1, and the distance between the oil pump The distance between the temperature measuring point at the outlet and the rear flange of the oil delivery pump outlet is greater than or equal to 3 times the outlet diameter D2, and the distance between the pressure measurement point and the rear flange of the oil delivery pump outlet is greater than or equal to 2 times the outlet diameter D2.

The test method of volume flow: if the SCADA system in the station collects the data of the measuring instruments in the station, the volume flow of crude oil is read through the SCADA system. When the conditions for collecting the flow rate of the oil pump in the station are not available, a portable flowmeter can be used for flow measurement. According to the provisions of GB/T 33216-1989 "Centrifugal Pump, Mixed Flow Pump, Axial Flow Pump and Vortex Pump Test Method", the crude oil volume flow rate is measured under the frequency conversion condition.

On-site parameter acquisition module 44, for utilizing the instrument after the test to carry out on-site testing to obtain on-site parameters;

Among them, the physical parameter test of crude oil includes crude oil density and crude oil viscosity at 20°C.

① Density of crude oil at 20°C

According to GB/T 1884-2000 "Laboratory Determination of Density of Crude Oil and Liquid Petroleum Products (Density Meter Method)", use a density meter to test the density ρ of crude oil.

② Crude Oil Viscosity

According to SY/T 0520-2008 "Crude Oil Viscosity Determination Rotational Viscometer Balance Method", use a viscometer to test the crude oil kinetic viscosity μ.

The energy efficiency acquisition module 45 is used to calculate by using the energy efficiency model of the variable frequency oil pump unit according to the motor test parameters, the oil pump test parameters, the field parameters, the motor test parameters under variable frequency conditions, and the oil pump test parameters under variable frequency conditions, so as to realize the variable frequency output. Energy efficiency test of oil pump unit.

Field application examples:

From August to September 2011, the energy efficiency test of the frequency conversion oil pump unit was carried out at the Weigang oil transfer station of the Weijing pipeline. According to the test data and energy efficiency calculation results, the energy consumption level and energy saving benefits of the frequency conversion oil transfer pump unit of the Weigang oil transfer station were analyzed .

1. On-site test data of frequency conversion oil pump unit in Weigang Oil Station

When the flow rates are 153m ³ /h, 164m ³ /h, 175m ³ /h and 185m ³ /h respectively, the power frequency and variable frequency operating conditions are used to operate respectively, and only the measurement data and calculation process of the variable frequency operating condition are given here.

1) The physical properties of the crude oil transported

Sampling was carried out to test the density of crude oil transported by Weigang Oil Station at 20°C and the corresponding viscosity at the test temperature. The specific results are shown in Table 1.

Table 1 Physical parameters of crude oil

2) Test data of oil delivery pump unit under frequency conversion condition

(1) Control the opening of the outlet valve of the oil pump to 100%, adjust the frequency of the frequency converter to 37.0Hz, and conduct the first energy efficiency test of Weigang Oil Station;

(2) Adjust the inverter frequency to 38.4Hz, and conduct the second energy efficiency test;

(3) Adjust the inverter frequency to 39.9Hz, and conduct the third energy efficiency test;

(4) Adjust the inverter frequency to 42.0Hz, and conduct the fourth energy efficiency test.

See Table 2 for the field test data of the oil pump, and Table 3 for the field test data of the motor.

Table 2 Test parameters of oil delivery pump under frequency conversion condition

Table 3 Motor test parameters under variable frequency conditions

2. Calculation and analysis of energy efficiency of oil delivery pump unit under frequency conversion condition

1) Energy efficiency calculation

The actual ex-factory efficiency of the oil pump when transporting the test crude oil is obtained by interpolating the viscosity of the crude oil during the test based on the efficiency measured by the manufacturer when this type of oil pump transports clean water and 162mPa·s crude oil, see Table 4 for details. Among them, the temperature corresponding to the viscosity of crude oil during the test is the average value of the crude oil temperature at the inlet and outlet of the oil transfer pump. The viscosity of crude oil during the test is obtained by interpolating the temperature according to the data in Table 4.

The energy efficiency calculation under the frequency conversion condition adopts the pump temperature difference method. The specific calculation results are shown in Table 5, and the energy efficiency analysis of the oil delivery pump unit is carried out by comparing the performance conversion values of the oil delivery pump in Table 4.

Table 4 Conversion value of oil delivery pump performance under frequency conversion condition

Table 5 Calculation results using the pump temperature difference method under variable frequency conditions

Under the condition of frequency conversion, the efficiency of the oil delivery pump calculated by the temperature difference method over the pump is lower than the efficiency of clean water and the actual delivery when the crude oil flow rate is 153m ³ /h, 164m ³ /h, 175m ³ /h and 185m ³ /h The ex-factory efficiency of crude oil, the calculation result is reasonable.

2) Benefit analysis

(1) The efficiency of the oil delivery pump is calculated by the temperature difference method of the pump. The average efficiency of the oil delivery pump under the frequency conversion condition is 67.41%, and the average efficiency of the oil delivery pump under the power frequency condition is 60.86%. When the crude oil flow rate is 153m ³ /h, 164m ³ /h, 175m ³ /h and 185m ³ /h respectively, the efficiency of the oil delivery pump under the frequency conversion condition is higher than that under the power frequency condition.

Calculated on the basis of 8400 hours of oil pump operation per year, when the crude oil flow rate is 153m ³ /h, the annual energy saving under the frequency conversion condition is 1171.8MW·h compared with the power frequency condition; when the crude oil flow rate is 164m ³ /h, the annual energy saving is 976.6MW·h ; When the crude oil flow rate is 175m ³ /h, the annual energy saving is 990.2MW·h; when the crude oil flow rate is 185m ³ /h, the annual energy saving is 855.1MW·h; Among them, the economic benefit can reach up to 937,000 yuan per year.

(2) The motor efficiency is calculated by the pump temperature difference method. Under the frequency conversion condition, when the crude oil flow rate is 153m ³ /h, 164m ³ /h, 175m ³ /h and 185m ³ /h respectively, the motor efficiency is lower than the power frequency condition lower motor efficiency. When calculating the efficiency of the motor under variable frequency conditions, the frequency converter and the motor are considered as a whole, which is also an energy-consuming device and consumes a certain amount of electric energy.

(3) The efficiency of the oil delivery pump unit is calculated by the temperature difference method of the pump. The average efficiency of the oil delivery pump unit under the frequency conversion condition is 50.57%, and the average efficiency of the oil delivery pump unit under the power frequency condition is 49.37%. When the crude oil flow rate is 153m ³ /h, 164m ³ /w, 175m ³ /h and 185m ³ /h, the efficiency of the oil delivery pump unit under the frequency conversion condition is higher than that under the power frequency condition.

Calculated on the basis of 8400 hours of oil pump operation per year, when the crude oil flow rate is 153m ³ /h, the annual energy saving under the frequency conversion condition is 1215.6MW·h compared with the power frequency condition; when the crude oil flow rate is 164m ³ /h, the annual energy saving is 1232.87MW·h ; When the crude oil flow rate is 175m ³ /h, the annual energy saving is 1114.4MW·h; when the crude oil flow rate is 185m ³ /h, the annual energy saving is 910.1MW·h; Among them, the economic benefit can reach up to 986,000 yuan per year.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims (16)

1. A method for testing the energy efficiency of a variable frequency oil delivery pump unit, characterized in that it comprises: Calculate the efficiency of the frequency conversion oil pump; Calculate the input power of the variable frequency motor; Calculate the output power of the oil transfer pump under the frequency conversion condition; Calculate the input power of the oil pump under the frequency conversion condition through the output power of the oil pump under the frequency conversion condition; Calculate the output power of the motor under the frequency conversion condition through the input power of the oil pump under the frequency conversion condition; The efficiency of the variable frequency motor is calculated by the input power of the variable frequency motor and the output power of the motor under variable frequency conditions; The energy efficiency of the frequency conversion oil pump unit is tested by the efficiency of the frequency conversion oil pump and the efficiency of the frequency conversion motor. 2. The method for testing the energy efficiency of the variable frequency oil delivery pump unit according to claim 1, wherein said testing the energy efficiency of the frequency conversion oil delivery pump unit through the efficiency of the frequency conversion oil delivery pump and the efficiency of the frequency conversion motor comprises: According to the energy efficiency model of the frequency conversion oil pump unit, the field parameters required for the field test are determined; Select instruments according to site parameters, and test the selected instruments; According to the energy efficiency model of the variable frequency oil delivery pump unit, the motor and the oil delivery pump are tested to obtain the motor test parameters, the oil delivery pump test parameters, the motor test parameters under the frequency conversion condition, and the oil delivery pump test parameters under the frequency conversion condition; Use the tested instruments to conduct on-site tests to obtain on-site parameters; According to the motor test parameters, oil pump test parameters, field parameters, motor test parameters under variable frequency conditions and oil pump test parameters under variable frequency conditions, the energy efficiency model of the variable frequency oil pump unit is used for calculation to realize the energy efficiency test of the variable frequency oil pump unit. 3. The method for testing the energy efficiency of the variable frequency oil delivery pump unit according to claim 1, wherein the calculation of the output power of the motor under the variable frequency working condition comprises: Neglecting the power loss in the transmission process, according to the principle of energy conservation, the power of the output shaft of the transmission mechanism is equal to the power of the input shaft, that is, the output power of the motor under the condition of frequency conversion is equal to the input power of the oil pump under the condition of frequency conversion. The output power of the motor under the frequency conversion condition is obtained from the input power of the oil delivery pump under the frequency conversion condition obtained in the calculation steps of the input power of the oil delivery pump under the frequency conversion condition. 4. The method for testing the energy efficiency of the variable frequency oil pump unit according to any one of claims 1 to 3, wherein the calculation of the input power of the variable frequency motor includes: The parameters required for calculating the input power of the variable frequency motor are measured, and the input power of the variable frequency motor is calculated according to the parameters. 5. The method for testing the energy efficiency of the variable frequency oil pump unit according to claim 4, wherein the method for measuring the parameters required for calculating the input power of the variable frequency motor is the electric energy meter method. 6. The method for testing the energy efficiency of the variable frequency oil pump unit according to claim 4, wherein the method for measuring the parameters required for calculating the input power of the variable frequency motor is the current and voltage power factor method. 7. The method for testing the energy efficiency of the frequency conversion oil pump unit according to claim 2, wherein the instrument comprises: a power analyzer, a float type density meter, a viscometer, a hand-held laser tachometer, a portable flowmeter and glass mercury thermometer. 8. The energy efficiency testing method of the frequency conversion oil delivery pump unit according to claim 2, wherein the test parameters of the oil delivery pump include inlet crude oil temperature, outlet crude oil temperature, inlet crude oil pressure, outlet crude oil pressure, crude oil density and measured crude oil volume flow. 9. The method for testing the energy efficiency of the frequency conversion oil pump unit according to claim 2, wherein the test parameters of the oil pump under the frequency conversion condition include inlet and outlet temperature, pressure and volume flow. 10. An energy efficiency testing device for a variable frequency oil delivery pump unit, characterized in that it includes: The frequency conversion oil pump efficiency unit is used to calculate the efficiency of the frequency conversion oil pump; The variable frequency motor input power unit is used to calculate the input power of the variable frequency motor; The output power unit of the oil delivery pump under the frequency conversion condition is used to calculate the output power of the oil delivery pump under the frequency conversion condition; The input power unit of the oil delivery pump under the frequency conversion condition is used to calculate the input power of the oil delivery pump under the frequency conversion condition through the output power of the oil delivery pump under the frequency conversion condition; Motor output power unit under frequency conversion condition, which is used to calculate the output power of motor under frequency conversion condition through the input power of oil pump under frequency conversion condition; The variable frequency motor efficiency unit is used to calculate the variable frequency motor efficiency through the input power of the variable frequency motor and the output power of the motor under the variable frequency working condition; The energy efficiency test unit of the frequency conversion oil pump unit is used to test the energy efficiency of the frequency conversion oil pump unit through the efficiency of the frequency conversion oil pump and the efficiency of the frequency conversion motor. 11. The energy efficiency testing device of the frequency conversion oil pump unit according to claim 10, wherein the energy efficiency test unit of the frequency conversion oil pump unit comprises: The on-site parameter determination module is used to determine the on-site parameters required for on-site testing according to the energy efficiency model of the variable frequency oil delivery pump unit; The instrument test module is used to select instruments according to field parameters and test the selected instruments; The test parameter acquisition module is used to obtain the test parameters of the motor, the test parameters of the oil pump, the test parameters of the motor under the frequency conversion condition and the test parameters of the oil delivery pump under the frequency conversion condition through the test of the motor and the oil delivery pump according to the energy efficiency model of the variable frequency oil delivery pump unit; The on-site parameter acquisition module is used to use the tested instrument to perform on-site testing to obtain on-site parameters; The energy efficiency acquisition module is used to calculate by using the energy efficiency model of the variable frequency oil pump unit according to the motor test parameters, the oil pump test parameters, the field parameters, the motor test parameters under variable frequency conditions, and the oil pump test parameters under variable frequency conditions to realize the variable frequency oil pump Unit energy efficiency test. 12. The energy efficiency testing device of the frequency conversion oil pump unit according to claim 10, wherein the calculation of the output power of the motor under the frequency conversion condition by the motor output power unit under the frequency conversion condition includes: Neglecting the power loss in the transmission process, according to the principle of energy conservation, the power of the output shaft of the transmission mechanism is equal to the power of the input shaft, that is, the output power of the motor under the condition of frequency conversion is equal to the input power of the oil pump under the condition of frequency conversion. The output power of the motor under the frequency conversion condition is obtained from the input power of the oil delivery pump under the frequency conversion condition obtained in the calculation steps of the input power of the oil delivery pump under the frequency conversion condition. 13. The energy efficiency testing device of the variable frequency oil pump unit according to any one of claims 10 to 12, wherein the calculation of the input power of the variable frequency motor by the variable frequency motor input power unit includes: The parameters required for calculating the input power of the variable frequency motor are measured, and the input power of the variable frequency motor is calculated according to the parameters. 14. The energy efficiency testing device of variable frequency oil pump unit according to claim 11, characterized in that, the instruments selected by the instrument testing module include: power analyzers, float density meters, viscometers, hand-held laser tachometers, portable flow meters Gauge And Glass Mercury Thermometer. 15. The energy-efficiency testing device of the frequency conversion oil delivery pump unit according to claim 11, wherein the test parameters of the oil delivery pump acquired by the test parameter acquisition module include inlet crude oil temperature, outlet crude oil temperature, inlet crude oil pressure, outlet crude oil pressure, Crude oil density and measured crude oil volume flow. 16. The energy efficiency testing device of the frequency conversion oil pump unit according to claim 11, wherein the test parameters of the oil pump under variable frequency conditions obtained by the test parameter acquisition module include inlet and outlet temperature, pressure and volume flow.

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