Wellhead safety test box in artificial lift systems

Abstract

The utility model discloses a wellhead safety test box in manual lifting system, shell and the circuit board of setting in the shell inside, the circuit board includes: external power supply circuit, internal power supply circuit, isolation circuit and control circuit, the input of external power supply circuit is connected alternating current, and the output is connected UPS, one output interface of UPS connects internal power supply circuit, and the output interface of another connects control circuit, the control signal input of control circuit is connected isolation circuit, utilizes control circuit and isolation circuit, and motor power cable is connected access test box correspondingly, can real -time detection well PMM motor's regenerative high -voltage electric energy and motor together with cable's insulation condition, if finds the abnormality, and the on -the -spot personnel can make the judgement rapidly, reduces the influence to the oil exploitation progress.

Description

Technical Field

[0001] This utility model relates to the field of lifting control circuit technology in the petroleum industry, and in particular to a wellhead safety test box in an artificial lifting system. Background Technology

[0002] The electrical control system of an electric submersible pump (ESP) using a permanent magnet motor (PMM) is responsible for extracting and transporting oil from downhole wells. During equipment maintenance and repair work, when power is cut off on-site, only the equipment above ground is kept in a powered-off and stopped state. It cannot visually assess the situation at the motor thousands of meters down the well, nor can it determine the motor's condition or integrity. Due to the complexity of the downhole environment, the motor may rotate due to external forces from the downhole fluid, even when not under the control of the electrical system. When the motor is forced to rotate, regardless of the direction of rotation, it generates internal voltage, essentially creating a secondary power source lurking beneath the surface. This is undetectable to operators and poses a significant safety hazard. Therefore, a safety warning testing device is needed. Utility Model Content

[0003] Therefore, the purpose of this invention is to provide a wellhead safety test box for an artificial lift system, which can continuously monitor the dangerous voltage generated by the motor being forced to rotate by external forces downhole, while also measuring the insulation condition of the motor's three-phase windings. This ensures the safety of operators while improving the efficiency of equipment maintenance and reducing economic losses during oil pump and cable deployment operations.

[0004] To achieve the above objectives, this utility model provides a wellhead safety test box in an artificial lifting system, comprising: a shell and a circuit board disposed inside the shell. The circuit board includes: an external power supply circuit, an internal power supply circuit, an isolation circuit, and a control circuit. The input terminal of the external power supply circuit is connected to AC power, and the output terminal is connected to a UPS. One output interface of the UPS is connected to the internal power supply circuit, and the other output interface is connected to the control circuit. The control signal input terminal of the control circuit is connected to the isolation circuit.

[0005] More preferably, the external power supply circuit includes an AC power interface and a rectifier element; after the AC power interface is connected to AC power, the AC power is connected to the input terminal of the rectifier element, and the output terminal of the rectifier element outputs DC power.

[0006] More preferably, the control circuit employs a differential amplifier, an operational amplifier, and a comparator; the input interface of the differential amplifier is connected to the motor detection signal, the output terminal of the differential amplifier is connected to the input terminal of the operational amplifier, and the output terminal of the operational amplifier is connected to the output terminal of the comparator; the output terminal of the comparator is connected to an optocoupler-isolated output, and the output interface is connected to an alarm indicator light.

[0007] More preferably, the isolation circuit includes a rotary switch connected to a three-phase motor; the other end of the rotary switch is grounded.

[0008] More preferably, the U, V, and W phase lines of the three-phase motor are connected to a megohmmeter.

[0009] More preferably, a power indicator light is connected in parallel across the two ends of the power input terminal of the control circuit.

[0010] The wellhead safety test box in the artificial lift system disclosed in this application utilizes control and isolation circuits to connect the motor power cable to the test box, enabling real-time monitoring of the regenerative high-voltage power of the downhole PMM motor and the insulation condition of the motor and its cable. When regenerative power is detected, the device displays the voltage value and issues a danger warning simultaneously. An external insulation tester measures the resistance value of the motor and its cable, recording the downhole motor's insulation condition in real time. If an abnormality is detected, on-site personnel can quickly make a judgment, minimizing the impact on oil extraction progress. An isolation grounding function is added to disconnect the high-voltage motor from the ground to prevent injury to personnel or damage to surface equipment. Attached Figure Description

[0011] Figure 1 A schematic diagram of the wellhead safety test box in the artificial lift system provided by this utility model.

[0012] Figure 2 This is a circuit diagram of the input terminal of the control circuit in this utility model.

[0013] Figure 3 This is a circuit diagram of the output terminal of the control circuit in this utility model. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] like Figure 1 As shown, one embodiment of the present invention provides a wellhead safety test box in an artificial lifting system, comprising: a shell and a circuit board disposed inside the shell. The circuit board includes: an external power supply circuit 1, an internal power supply circuit 2, an isolation circuit 3, and a control circuit 4. The input terminal of the external power supply circuit is connected to an AC LN line, and the output terminal is connected to a UPS. One output interface of the UPS is connected to the internal power supply circuit (which is a battery), and the other output interface (DC output) is connected to the control circuit. The control signal input terminal of the control circuit is connected to the isolation circuit.

[0016] The external power supply circuit includes an AC interface and a rectifier; after the AC interface is connected to AC power, the AC power is connected to the input terminal of the rectifier, and the output terminal of the rectifier outputs DC power.

[0017] Example 1, such as Figure 1 The control circuit U2 described herein adopts a modular design, wherein the specific structure of the control circuit is as follows: Figure 2 and Figure 3 As shown, in Figure 2 In this application, J1 is an AC LN line formed by any two phases extracted from a three-phase power supply, which serves as the input signal. After rectification, it forms a DC voltage VE as the reference voltage output, and simultaneously forms V+ and V- outputs with equal amplitudes. In this application, both V+ and V- are 24V.

[0018] More preferably, the control circuit employs a differential amplifier, an operational amplifier, and a comparator; the input interface of the differential amplifier is connected to the motor detection signal, the output terminal of the differential amplifier is connected to the input terminal of the operational amplifier, and the output terminal of the operational amplifier is connected to the output terminal of the comparator; the output terminal of the comparator is connected to an optocoupler-isolated output, and the output interface is connected to an alarm indicator light.

[0019] J2 connects to any two phases drawn from the three-phase power supply; one phase is input into amplifier U1C, and the other phase is input into amplifier U1D; amplifiers U1C and U1D together form a differential amplifier, and VE is the reference voltage; resistors R21 / R22 / R3 / R5 / R4 / R6 in the figure form a grouped voltage network, which is used to step down the input voltage signal so that it can be acquired by the subsequent circuit. Zener diodes D1 and D2 are used to protect amplifiers U1C and U1D, respectively, ensuring that the operational amplifiers will not be damaged even in the event of an abnormal high-voltage transient pulse. The core purpose of the differential amplifier is to amplify the difference between two input signals while suppressing any common-mode signal. Therefore, the difference between the two input signals is differentially amplified. The amplified differential signal is then amplified by amplifier U1B and compared by comparator U1A. When the differential signal is greater than the reference voltage VE, a high level is output; when it is less than the reference voltage VE, a low level is output. After isolation by an optocoupler, the output is then cleared. When the output is high, the alarm indicator light turns on; when it is low, the alarm indicator light does not turn on, indicating that the system is in a safe state.

[0020] The input interface of the control circuit is connected to the motor detection signal. Figure 1 At the three-phase power connection point, when the motor stops running, the abnormal electromotive force output during inertial motion will be output in reverse in the three-phase power supply. Therefore, data can be collected at this point. The output interface is connected to an alarm indicator light.

[0021] The isolation circuit includes a rotary switch QS1 connected to a three-phase motor; the other end of the rotary switch is grounded.

[0022] In this application, the U, V, and W phase lines of the three-phase motor can also be connected to a megohmmeter.

[0023] A power indicator light is connected in parallel across the two ends of the power input terminal of the control circuit.

[0024] There are two ways to power the control circuit.

[0025] The instrument's control unit is powered by an external 220V AC power supply. This method can also be used to charge the instrument's internal battery. The internal battery provides control power, eliminating the need for an external 220V power supply.

[0026] The equipment can be used in three modes.

[0027] The early warning mode is used to detect the regenerative power supply that may generate dangerous voltages from the downhole motor. This means that even when the external 380V three-phase power supply stops, the motor continues to operate and generate voltage. In this case, connect the external motor leads to the reserved interface and check the voltmeter reading. When the voltmeter shows a voltage greater than 36V, the yellow light buzzer is activated, illuminating the yellow light and emitting a buzzer sound. This indicates that a dangerous voltage has been generated, and further operation should be stopped. Wait for the voltmeter reading to drop to 0 before proceeding to the next test. Alternatively, the control circuit can be used to determine the voltage using the process described in Example 1. When the generated regenerative voltage exceeds the threshold, the yellow light illuminates and a buzzer sounds, indicating that a dangerous voltage has been generated.

[0028] In safety mode, the instrument operates under warning conditions. The voltmeter reading stabilizes and remains at zero for a period of time, allowing for safety mode testing. To initiate a safety mode test, turn the panel grounding switch knob QS1 to the "ON" position, short-circuit the three-phase windings of the motor, and then connect them to ground. It is important to note that a safety mode test cannot be performed if the voltmeter reading is not zero or the alarm light is on.

[0029] In test mode, the instrument's voltmeter reading remains stable at 0 for an extended period before entering test mode. An insulation testing instrument is connected to the equipment's pre-installed interface on-site to test the insulation resistance of the motor windings and cables. If there are issues with the motor insulation, on-site personnel can quickly resolve the problem, preventing economic losses to the pumping project.

[0030] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A wellhead safety test kit for an artificial lift system, characterized in that, include: The housing and a circuit board disposed inside the housing, the circuit board including: an external power supply circuit, an internal power supply circuit, an isolation circuit and a control circuit; The input terminal of the external power supply circuit is connected to AC power, and the output terminal is connected to the UPS; one output interface of the UPS is connected to the internal power supply circuit, and the other output interface is connected to the control circuit; the control signal input terminal of the control circuit is connected to the isolation circuit.

2. The wellhead safety test box in the artificial lift system according to claim 1, characterized in that, The external power supply circuit includes an AC interface and a rectifier; after the AC interface is connected to AC power, the AC power is connected to the input terminal of the rectifier, and the output terminal of the rectifier outputs DC power.

3. The wellhead safety test box in the artificial lift system according to claim 1, characterized in that, The control circuit employs a differential amplifier, an operational amplifier, and a comparator. The input interface of the differential amplifier is connected to the motor detection signal, the output terminal of the differential amplifier is connected to the input terminal of the operational amplifier, and the output terminal of the operational amplifier is connected to the output terminal of the comparator. The output terminal of the comparator is connected to an optocoupler-isolated output, and the output interface is connected to an alarm indicator light.

4. The wellhead safety test box in the artificial lift system according to claim 1, characterized in that, The isolation circuit includes a rotary switch connected to a three-phase motor; the other end of the rotary switch is grounded.

5. The wellhead safety test box in the artificial lift system according to claim 4, characterized in that, The U, V, and W phase lines of the three-phase motor are connected to a megohmmeter.

6. The wellhead safety test box in the artificial lift system according to claim 3, characterized in that, A power indicator light is connected in parallel across the two ends of the power input terminal of the control circuit.

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