CN110261659A - A kind of monitoring system and method for the leakage current of electric submersible pump unit - Google Patents

Abstract

The embodiment of the present invention discloses a system and method for real-time monitoring of the leakage current of the submersible electric pump unit; the system includes: a closed-loop Hall current sensor, and the cable armor of the three-phase cable for powering the submersible electric pump passes through the The inner hole of the closed-loop Hall current sensor, so that the closed-loop Hall current sensor measures the magnitude of the leakage current in the AC form from the current flowing through the cable sheath and measures the magnitude of the leakage current converted into a DC analog value, wherein the current flowing through the cable sheath includes the leakage current in AC form and parameters in the DC form produced by a downhole measurement unit for measuring a plurality of downhole parameters of the electric submersible pump A current signal; a micro control unit configured to receive the DC analog value and compare the DC analog value with a leakage current threshold; an alarm module configured to alarm and enable the DC analog value to be greater than the leakage current threshold The electric submersible pump unit stops working.

Description

System and method for monitoring leakage current of submersible electric pump unit

technical field

The invention relates to the technical field of monitoring the electric submersible pump of oil exploitation equipment, in particular to a monitoring system and method for the leakage current of the electric submersible pump unit.

Background technique

Insulators are generally considered non-conductive, but in reality, almost no insulating material is absolutely non-conductive. Any kind of insulating material, when a voltage is applied across its two ends, there will always be a certain current passing through. The active component of this current is called leakage current, and this phenomenon is also called leakage of the insulator. In fact, leakage current is the current that flows through an insulating part of an electrical circuit or device when a voltage is applied without a fault. Therefore, the size of the leakage current is one of the important signs to measure the insulation performance of electrical appliances, and is the main indicator of product safety performance. Limiting the leakage current to a small value plays an important role in improving product safety.

In the field of oil exploration, under the action of voltage applied to the submersible electric pump unit without fault, a loop is formed between the three-phase wire and the cable armor at the aging insulation performance of the insulation layer of the three-phase cable, which will generate a leakage current . The downhole environment of oil production wells is very complex. For example, the downhole high temperature and high pressure environment and some oil well chemicals such as hydrogen sulfide and carbon dioxide will cause damage to the insulation of the transmission cable of the submersible electric pump unit, resulting in destructive failure of the system. Therefore, the measurement of the leakage current of the submersible electric pump unit is very important.

In the prior art, in order to ensure the safe use of the electric submersible pump, an insulation test is performed on the electric submersible pump unit before going into the well, that is, the leakage current of the electric submersible pump unit is measured. A 2.5KV-10KV megohmmeter is used in the measurement process. When measuring, connect the negative pole of the test lead to the phase line under test, and the positive pole of the test lead to ground. Although the output current of the megohmmeter is very small, if no protective measures are taken, the instantaneous high voltage generated by the megohmmeter will break down and damage the downhole equipment. Therefore, a high-voltage diode is also connected to the star point of the motor to protect the downhole equipment during the insulation test. Unless the high-voltage diode breaks down, the downhole equipment will not have instantaneous high-voltage current flow. The disadvantage of this method is that it can only guarantee the reliability of the insulation performance of the submersible electric pump unit before going into the well, and cannot measure the insulation performance of the submersible electric pump unit in real time. Once the insulation fails, without corresponding data support, the staff cannot There is no way to take corresponding solutions to estimate the working conditions of the submersible electric pump unit. If you want to know the insulation performance of the electric submersible pump unit under long-term operation, the electric submersible pump must stop working and pull out all the oil pipes, which is a waste of time and money.

Another way to detect the leakage current of the submersible electric pump unit is to connect a diode in antiparallel between the two poles of the power supply of the downhole parameter unit. When the secondary instrument on the well provides positive voltage, the diode does not conduct, and the downhole circuit can work normally. , which can detect parameters other than unit leakage current value. When the secondary instrument on the well provides downward back pressure, the anti-parallel diode is turned on, and the downhole circuit is bypassed, and other components cannot work at this time. The system current at this time is the leakage current of the submersible electric pump unit. The measurement of the neutral point leakage current is completed by detecting the current value in the loop. The disadvantage of this method is that the leakage current can only be measured when the reverse voltage is provided downhole, and it cannot be monitored in real time.

At this stage, there is a set of very mature measurement specifications for the measurement of leakage current of domestic household appliances, but this measurement method must be a testing organization with certain qualifications to measure electrical appliances. Users themselves cannot realize the measurement of leakage current without professional technical support.

Contents of the invention

In order to solve the above technical problems, the embodiment of the present invention expects to provide a leakage current monitoring system and method of the electric submersible pump unit; the leakage current monitoring can also be realized when the electric submersible pump is downhole and in working state; It does not need to provide back pressure to the downhole, and can realize real-time monitoring; the monitoring technology is simple, and there is no need to provide professional technical support for users.

Technical scheme of the present invention is realized like this:

In the first aspect, the embodiment of the present invention provides a system for real-time monitoring of the leakage current of the submersible electric pump unit, the system comprising:

Closed-loop Hall current sensor, the cable armor of the three-phase cable for powering the submersible electric pump passes through the inner hole of the closed-loop Hall current sensor, so that the closed-loop Hall current sensor flows through the cable armor Measure the magnitude of the leakage current in the AC form and convert the magnitude of the leakage current into a DC analog value, wherein the current flowing through the cable sheath includes the leakage current in the AC form and for A parameter current signal in the form of direct current generated by the downhole measurement unit for measuring multiple downhole parameters of the electric submersible pump;

a microcontroller unit configured to receive the DC analog value and compare the DC analog value with a leakage current threshold;

The alarm module is configured to alarm and stop the submersible electric pump unit when the DC analog value is greater than the leakage current threshold.

In the second aspect, the embodiment of the present invention provides a method for real-time monitoring of the leakage current of the submersible electric pump unit, the method is applied to the system described in the first aspect, and the method includes:

The closed-loop Hall current sensor measures the magnitude of the leakage current in AC form from the current flowing through the cable sheath and converts the magnitude of the leakage current into a DC analog value;

The micro control unit receives the DC analog value and compares the DC analog value with a leakage current threshold;

The alarm module alarms when the DC analog value is greater than the leakage current threshold and stops the submersible electric pump unit from working.

The embodiment of the present invention provides a monitoring system and method for the leakage current of the electric submersible pump unit; by using a closed-loop Hall current sensor on the ground to measure the leakage current, it is not necessary to lift all the electric submersible pump units out of the wellhead; the closed-loop Hall The current sensor can only measure the AC current value, and will not be affected by the DC parameter current signal that also flows through the cable armor, and can monitor the current leakage of the submersible electric pump unit in real time; the closed-loop Hall current sensor and the measured current flow There is no direct electrical connection between the loops, and the energy of the loop through which the measured current flows will not be consumed, and the impact on the loop is small, and the measured value is relatively accurate; the measurement method is simple and does not require the user to have professional skills.

Description of drawings

1 is a schematic diagram of a system for real-time monitoring of the leakage current of a submersible electric pump unit provided by an embodiment of the present invention;

2 is a schematic structural diagram of a submersible electric pump unit and a system for real-time monitoring of the leakage current of the submersible electric pump unit provided by an embodiment of the present invention;

3 is a schematic structural diagram of a closed-loop Hall current sensor provided by an embodiment of the present invention;

Fig. 4 is a schematic diagram of a method for real-time monitoring of leakage current of a submersible electric pump unit provided by an embodiment of 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 drawings in the embodiments of the present invention.

Referring to FIG. 1 , it shows a system 100 for real-time monitoring of leakage current LC of a submersible electric pump unit 200 provided by an embodiment of the present invention. Described electric submersible pump unit 200 comprises the electric submersible pump 230 (referring to Fig. 2) powered by three-phase AC power supply 210, wherein, three-phase AC power supply 210 is the submersible electric pump by three-phase cable 240 through frequency conversion controller 220 230 for power supply, the three-phase cable 240 includes a three-phase conductor 241 , a cable armor 242 and an insulating layer 243 between the three-phase conductor 241 and the cable armor 242 . The leakage current LC (shown by a solid arrow in FIG. 2 ) is when the electric submersible pump 230 is powered by the three-phase cable 240, at the place where the insulation performance of the insulating layer 243 is aging (for example, as shown in FIG. 2 ). The insulation aging point 244 at the insulation aging point 244) is the alternating current flowing through the cable armor 242 generated by the three-phase conductor 241 and the cable armor 242 forming a loop. The electric submersible pump unit 200 also includes a downhole measurement unit 250 (see FIG. 2 ) for measuring multiple downhole parameters (such as temperature, vibration, and pressure) of the electric submersible pump 230. The downhole measurement unit The parameter current signal PC (shown by a dotted arrow in FIG. 2 ) in the form of DC generated by 250 is transmitted to the ground through the cable armor 242, and the downhole measurement unit 250 is based on the star point O1 and the downhole star point O2. The point equipotential principle is powered. The system 100 includes:

Closed-loop Hall current sensor 110, the cable sheath 242 of the three-phase cable 240 of power supply for submersible electric pump 230 passes through the inner hole H (see Fig. 2) of described closed-loop Hall current sensor 110, so that the closed-loop Hall current sensor The current sensor 110 measures the magnitude of the leakage current LC in the AC form from the current flowing through the cable sheath 242 and converts the magnitude of the leakage current LC into a DC analog value, wherein the magnitude of the leakage current LC flowing through the cable The current of the armor 242 includes the leakage current LC in the AC form and the parameter current signal PC in the DC form generated by the downhole measurement unit 250 for measuring multiple downhole parameters of the electric submersible pump 230;

The micro control unit 120 is configured to receive the DC analog value and compare the DC analog value with a leakage current threshold;

The alarm module 130 is configured to alarm and stop the submersible electric pump unit 200 when the DC analog value is greater than the leakage current threshold.

The working principle of the closed-loop Hall current sensor 110 is as follows: the magnetic field generated by the measured current is induced by the Hall element 111 (see FIG. 4 ) of the closed-loop Hall current sensor 110, and the generated output signal drives the corresponding power transistor to conduct Through, a compensation current is generated, and the compensation current flows through the wound secondary coil to generate a magnetic field. The magnetic field is exactly opposite to the magnetic field generated by the measured current, and compensates the original magnetic field, so that the inductive output of the Hall element 111 decreases. When the magnetic field generated by the measured current is equal to the magnetic field generated by the compensation current, the compensation current no longer increases, the magnetic field induced by the Hall element is zero, and the closed-loop Hall current sensor measures the measured current through the compensation current. It can be seen from the above working principle that the closed-loop Hall current sensor 110 can only measure the AC current value, so it will not be affected by the DC parameter current signal PC transmitted from the underground through the cable armor 242, so that the submersible electric pump can be monitored in real time Current leakage of unit 200. Moreover, there is no direct electrical connection between the closed-loop Hall current sensor 110 and the loop through which the measured current flows, and does not consume the energy of the loop through which the measured current flows, and has little influence on the loop, and the measured value is more accurate.

In a preferred embodiment of the present invention, as shown in FIG. 2 , the system 100 may further include a display screen 140 configured to display the DC analog value received by the microcontroller unit 120 in real time.

In a preferred embodiment of the present invention, as shown in FIG. 2 , the system 100 may also include a host computer 150 configured to draw in real time the corresponding DC analog value received by the micro control unit 120 Insulation performance curve. The insulation performance of the electric submersible pump unit 200 is a variable that decays slowly, so the leakage current LC representing the insulation performance of the electric submersible pump unit 200 is also a quantity that requires long-term real-time monitoring. By drawing the leakage current value as a time-varying curve, the user can observe the change of the insulation performance of the submersible electric pump unit 200 over time, and can judge the aging degree of the insulation performance in time, and predict the insulation performance of the submersible electric pump unit 200. Insulation aging trend in order to take corresponding protective measures in time to ensure the safe operation of the submersible pump unit.

In a preferred embodiment of the present invention, as shown in FIG. 2 , the system 100 further includes a multi-channel analog quantity acquisition module 160, and the multi-channel analog quantity acquisition module 160 is configured to acquire the closed-loop Hall The current sensor 110 outputs the DC analog value and sends the DC analog value to the micro control unit 120 .

In a preferred embodiment of the present invention, as shown in FIG. 2 , the multi-channel analog quantity acquisition module 160 is further configured to acquire the parameter current signal transmitted through the cable sheath 242 through a second channel and convert the The parameter current signal is sent to the micro control unit 120 .

FIG. 2 also shows the power supply for the closed-loop Hall current sensor 110 , the micro control unit 120 , the analog quantity acquisition module 160 and the downhole measurement unit 250 . Referring to FIG. 2 , power supply modules S1 - S3 are installed on the Inoue power board SP, and these power supply modules are supplied with electric energy by, for example, an 85-265VAC power supply S shown in FIG. 2 . The power supply module S1 is, for example, a switching power supply, which provides a dual power supply voltage of ±12V for the closed-loop Hall current sensor 110 and provides a 12V power supply voltage for the multi-channel analog quantity acquisition module 160; the power supply module S2 is, for example, an AC model MTW3-S5H The /DC module provides a power supply voltage of 5V for the micro control unit 120; the power supply module S4 provides electric energy for the downhole measurement unit 250 through the filter circuit 251 and the three-phase reactance winding 252, and the power supply module S4 is, for example, the AC/ DC module to generate 60V downhole power supply voltage.

Regarding the closed-loop Hall current sensor 110 described above, FIG. 3 shows a schematic structural diagram of a closed-loop Hall current sensor 110 provided by an embodiment of the present invention. As shown in FIG. 3 , the closed-loop Hall current sensor 110 includes a closed-loop Hall element 111 and a transmitter 112, and the closed-loop Hall element 111 measures a current without direct electrical connection with the cable sheath 242. The magnitude of the leakage current LC, in order for the microcontroller unit 120 to receive the leakage current signal, the transmitter 112 converts the magnitude of the leakage current LC into the DC analog value. The transmitter 112 includes four interfaces, the first interface I1 and the second interface I2 are dual power supply interfaces, the third interface I3 is grounded, and the fourth interface I4 is a transmission output interface, for example, it can be produced by Shandong Yuanxing Electronics. The leakage current transmitter converts the input 0-50mA AC current into a 4-20mA standard DC current signal for transmission and output.

Referring to the above system, refer to FIG. 4, which shows a method for real-time monitoring of the leakage current LC of the submersible electric pump unit 200 provided by the embodiment of the present invention. A system for the leakage current LC of the oil-electric pump unit 200, the method includes:

S401: The closed-loop Hall current sensor 110 measures the magnitude of the leakage current LC in AC form from the current flowing through the cable sheath 242 and converts the magnitude of the leakage current LC into a DC analog value;

S402: The microcontroller unit 120 receives the DC analog value and compares the DC analog value with a leakage current threshold;

S403: The alarm module 130 alarms and stops the submersible electric pump unit 200 when the DC analog value is greater than the leakage current threshold.

Regarding the technical solution shown in FIG. 4 , in a preferred implementation manner, the method further includes displaying the DC analog value received by the micro control unit 120 in real time on the display screen 140 .

Regarding the technical solution shown in FIG. 4 , in a preferred embodiment, the method further includes the host computer 150 drawing an insulation performance curve corresponding to the DC analog value received by the micro control unit 120 in real time.

Regarding the technical solution shown in FIG. 4 , in a preferred embodiment, the method further includes the multi-channel analog quantity acquisition module 160 acquiring the DC analog value output by the closed-loop Hall current sensor 110 through the first channel and Send the collected DC analog value to the micro control unit 120 .

It should be noted that: the technical solutions described in the embodiments of the present invention can be combined arbitrarily if there is no conflict.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. Should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (10)

1. a kind of system for the leakage current for monitoring electric submersible pump unit in real time characterized by comprising

Closed-loop Hall current sensor, the cable armour skin for the threephase cable of submersible electric pump power supply pass through the closed loop Hall current The inner hole of sensor, so that the closed-loop Hall current sensor measures exchange from the electric current for flowing through the cable armour skin The size of the leakage current is simultaneously converted into DC simulation value by the size of the leakage current of form, wherein is flowed through described The electric current of cable armour skin includes the leakage current of form of communication and multiple downhole parameters for measuring the submersible electric pump Underground survey unit generate DC form parameter current signal；

Micro-control unit is configured to receive the DC simulation value and compares the DC simulation value with leakage current threshold value Compared with；

Alarm module is configured to when the DC simulation value is greater than the leakage current threshold value alarm and makes the submersible electric pump Unit stops working.

2. system according to claim 1, which is characterized in that the system also includes display screen, the display screen configuration The DC simulation value received for micro-control unit described in real-time display.

3. system according to claim 1, which is characterized in that the system also includes host computer, the host computer configuration For real-time rendering insulation performance curve corresponding with the DC simulation value that the micro-control unit receives.

4. system according to claim 1, which is characterized in that the system also includes multichannel analog amount acquisition module, The multichannel analog amount acquisition module is configured to acquire the institute of the closed-loop Hall current sensor output by first passage It states DC simulation value and the DC simulation value is sent to the micro-control unit.

5. system according to claim 4, which is characterized in that the multichannel analog amount acquisition module is further configured to The parameter current signal transmitted via the cable armour skin is acquired by second channel and sends out the parameter current signal Give the micro-control unit.

6. system according to claim 1, which is characterized in that the closed-loop Hall current sensor includes closed loop Hall member Part and transmitter, the closed loop Hall element are measured described with the cable armour skin without being directly electrically connected The size of the leakage current is converted into the DC simulation value by the size of leakage current, the transmitter.

7. a kind of method for the leakage current for monitoring electric submersible pump unit in real time, which is characterized in that the method is applied to right It is required that system described in any one of 1 to 8, which comprises

Closed-loop Hall current sensor measures the big of the leakage current of form of communication from the electric current for flowing through cable armour skin It is small and the size of the leakage current is converted into DC simulation value；

Micro-control unit receives the DC simulation value and is compared the DC simulation value with leakage current threshold value；

Alarm module is greater than the leakage current threshold value alarm in the DC simulation value and stops the electric submersible pump unit Only work.

8. the method according to the description of claim 7 is characterized in that the method also includes micro-controls described in display screen real-time display The DC simulation value that unit processed receives.

9. the method according to the description of claim 7 is characterized in that the method also includes host computer real-time rendering with it is described micro- The corresponding insulation performance curve of the DC simulation value that control unit receives.

10. the method according to the description of claim 7 is characterized in that the method also includes multichannel analog amount acquisition modules The DC simulation value of closed-loop Hall current sensor output is acquired by first passage and by the DC simulation value It is sent to the micro-control unit.