Speed regulation system of underwater high-voltage motor

Abstract

The utility model discloses a speed regulation system of an underwater high-voltage motor. The speed regulation system comprises a circuit breaker, a frequency converter, a reactor, a transformer, a current transformer and a high-voltage motor which are sequentially connected in series, wherein 380V three-phase voltage is connected into the circuit breaker, the 380V three-phase voltage is subjected to speed regulation through the low-voltage frequency converter and is filtered through the reactor module, the 380V voltage is converted into high voltage through the boosting module and is transmitted to the high-voltage motor, the high-voltage current transformer is used for monitoring the current of the motor, and when the current is abnormal, the protection loop disconnects the low-voltage circuit breaker, so that the high-voltage motor is started. Therefore, the motor is protected. According to the system, the low-voltage frequency converter and the low-voltage reactor are utilized, and the size and the cost of equipment are effectively reduced while the speed regulation requirement of the underwater high-voltage motor is met.

Description

Technical Field

[0001] The utility model belongs to the technical field of motors, and particularly relates to a speed regulation system for an underwater high-voltage motor. Background Art

[0002] For the existing underwater high-voltage motor speed regulation device, generally a high-voltage transformer T1 is used to convert the incoming 380V into high voltage. The function of the SST1 high-voltage frequency converter is to control the voltage and frequency according to the V / F control mode, so as to control the speed of the motor. The function of the L1 high-voltage reactor is filtering. Since the output of the frequency converter is a square wave rather than a sine wave, when transmitting over a long distance, the square wave needs to be converted into a sine wave through the high-voltage reactor and finally output to the high-voltage motor to achieve the speed regulation function. This kind of speed regulation method is relatively traditional. This scheme uses a high-voltage circuit breaker, a high-voltage frequency converter, and a high-voltage reactor. These high-voltage components are all relatively large in volume and expensive in price. Content of the Utility Model

[0003] In order to overcome the deficiencies of the prior art, the utility model provides a speed regulation system for an underwater high-voltage motor to solve the problem of relatively high implementation cost in the prior art.

[0004] One embodiment of the utility model provides a speed regulation system for an underwater high-voltage motor, which is characterized in that the speed regulation system includes a circuit breaker, a frequency converter, a reactor, a transformer, a current transformer assembly and a high-voltage motor connected in series in sequence; wherein, the input end of the circuit breaker is connected to a 380V three-phase voltage; the current transformer assembly includes two high-voltage current transformers configured in parallel.

[0005] The incoming terminals L1, L2, and L3 of the three-phase power supply are connected to a 380V three-phase alternating current. This alternating current first enters a low-voltage frequency converter. The main function of the low-voltage frequency converter is to adjust the frequency of the output voltage by changing the frequency of the power supply, thereby achieving the control of the motor speed. Although it has the same function as a high-voltage frequency converter, it is smaller in size and more economical in price. The current output from the low-voltage frequency converter then passes through a low-voltage reactor. The function of the low-voltage reactor is similar to that of a high-voltage reactor, used for filtering to reduce the harmonic components in the current and improve the stability and reliability of the circuit. It has advantages in terms of price and volume, being more economical and occupying less space. The current filtered by the reactor is raised to a level suitable for the operation of the high-voltage motor through a step-up transformer. Then, the high-voltage electricity is transmitted to the high-voltage motor to drive the motor to operate. In the circuit, the current transformer module is used to monitor the current of the motor. They detect the working current of the motor in real time and feed the current signal back to the protection circuit. When an abnormal current situation occurs, such as excessive current or instability, the protection circuit will immediately act to disconnect the circuit breaker module, and its disconnection operation can quickly cut off the circuit, thereby protecting the motor from damage and preventing motor failures or other safety problems that may be caused by overcurrent

[0006] In one embodiment, the frequency converter is a low-voltage frequency converter, including the ACS510 series frequency converter.

[0007] In one embodiment, the reactor is a low-voltage reactor, including a core-adjustable inductance element.

[0008] In one embodiment, the low-voltage reactor includes the ACL-200 series low-voltage reactor.

[0009] In one embodiment, the transformer is a step-up transformer, including a three-phase transformer.

[0010] In one embodiment, the transformer further includes a temperature sensor, and the temperature sensor is disposed on the surface of the transformer for monitoring the temperature of the step-up transformer.

[0011] In one embodiment, the current transformer further includes an overcurrent relay, and the overcurrent relay is electrically connected to the current transformer module.

[0012] In one embodiment, the high-voltage motor further includes a thermal relay, and the thermal relay is connected in series with the high-voltage motor winding.

[0013] In one embodiment, the transformer further includes a gas relay, and the gas relay is disposed inside the step-up transformer for detecting internal faults of the transformer.

[0014] The speed regulation system of an underwater high-voltage motor provided by the above embodiments has the following beneficial effects:

[0015] For the speed regulation system of an underwater high-voltage motor provided by the present invention, a 380V voltage is input through a three-phase power supply, and speed regulation is performed through a low-voltage frequency converter. Then, after passing through a low-voltage reactor and being filtered by the reactor, the 380V voltage is transformed into high voltage by a transformer and transmitted to the high-voltage motor. The function of the high-voltage current transformer is to monitor the current of the motor. When the current is abnormal, the protection circuit will disconnect the low-voltage circuit breaker to protect the motor. In the past, high-voltage motors using high-voltage components were bulky and expensive to use. In contrast, the advantage of the speed regulation circuit provided in this application is that it uses a low-voltage frequency converter and a low-voltage reactor, effectively reducing the volume and cost of the equipment while meeting the speed regulation requirements of the underwater high-voltage motor. By boosting the voltage through a transformer, it ensures that the high-voltage motor can obtain the required high voltage, and the setting of the current monitoring and protection circuit enhances the safety and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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 required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0017] Figure 1 It is a schematic connection structure diagram of a speed regulation system of an underwater high-voltage motor in the prior art provided by an embodiment of the present invention;

[0018] Figure 2 It is a schematic connection structure diagram of a speed regulation system of an underwater high-voltage motor provided by an embodiment of the present invention;

[0019] Figure 3 It is a schematic circuit connection diagram of a speed regulation system of an underwater high-voltage motor of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] 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. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0021] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present utility model, then such directional indications are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture. If this specific posture changes, then the directional indications will also change accordingly.

[0022] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present utility model, then such descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, or scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0023] Reference Figure 1 , Figure 1 For the conventional underwater high-voltage motor speed regulation method in the prior art, the three-phase power supply inlets L1, L2, and L3 are 380V. After the high-voltage transformer T1 transforms the incoming 380V into high voltage, the function of the SST1 high-voltage frequency converter is to control the voltage and frequency according to the V / F control mode, thereby controlling the speed of the motor. The function of the L1 high-voltage reactor is filtering. Since the output of the frequency converter is a square wave rather than a sine wave, when transmitting over a long distance, the square wave needs to be converted into a sine wave through the high-voltage reactor and finally output to the high-voltage motor to achieve the speed regulation function. This kind of speed regulation method is relatively traditional. This solution uses a high-voltage circuit breaker, a high-voltage frequency converter, and a high-voltage reactor. These high-voltage components are all relatively large in volume and expensive in price.

[0024] Embodiment 1

[0025] Reference Figures 2 - 3 , one embodiment of the present utility model provides a speed regulation system for an underwater high-voltage motor, characterized in that the speed regulation system includes a circuit breaker, a frequency converter, a reactor, a transformer, a current transformer assembly, and a high-voltage motor connected in series in sequence; wherein, the input end of the circuit breaker is connected to a 380V three-phase voltage; the current transformer assembly includes two high-voltage current transformers configured in parallel.

[0026] The incoming terminals L1, L2, and L3 of the three-phase power supply are connected to 380V three-phase alternating current. This alternating current first enters the low-voltage frequency converter. The main function of the low-voltage frequency converter is to adjust the frequency of the output voltage by changing the frequency of the power supply, thereby achieving the control of the motor speed. Although it has the same function as the high-voltage frequency converter, it is smaller in volume and more economical in price. The current output from the low-voltage frequency converter then passes through the low-voltage reactor. The function of the low-voltage reactor is similar to that of the high-voltage reactor, which is used for filtering to reduce the harmonic components in the current and improve the stability and reliability of the circuit. It has advantages in terms of price and volume, being more economical and occupying less space. The current filtered by the reactor is raised to a level suitable for the operation of the high-voltage motor through a step-up transformer. Then, the high voltage is transmitted to the high-voltage motor to drive the motor to operate. In the circuit, the current transformer module is used to monitor the current of the motor. They detect the working current of the motor in real time and feed the current signal back to the protection circuit. When an abnormal current situation occurs, such as excessive current or instability, the protection circuit will act immediately to disconnect the circuit breaker. Its disconnection operation can quickly cut off the circuit, thereby protecting the motor from damage and preventing motor failures or other safety problems that may be caused by overcurrent. The advantage of this speed regulation circuit is that it utilizes the low-voltage frequency converter and the low-voltage reactor, effectively reducing the volume and cost of the equipment while meeting the speed regulation requirements of the underwater high-voltage motor. Through transformer step-up, it ensures that the high-voltage motor can obtain the required high voltage. The setting of the current monitoring and protection circuit enhances the safety and stability of the system.

[0027] In one of the embodiments, the frequency converter includes a low-voltage frequency converter, and the low-voltage frequency converter can be optionally an ACS510 series frequency converter. The ACS510 series frequency converter has the following advantages: According to the vector control principle, vector control technology is adopted to achieve high-performance control, including speed closed-loop control and torque control; internal control algorithms are adopted, and a variety of control algorithms are integrated internally, including PID control, vector control algorithms, etc., which can adjust the operating state of the motor according to different working conditions and control requirements, thereby achieving efficient and stable operation. It has a variety of protection functions, including overcurrent protection, overvoltage protection, undervoltage protection, etc. When an abnormal situation occurs in the motor or the frequency converter, protection measures can be taken in a timely manner to ensure the safety of the equipment and personnel.

[0028] The circuit breaker provided in this embodiment is an important protection and control device in the power system. It can quickly cut off the circuit when abnormal conditions such as excessive current and short circuit are detected, so as to prevent equipment damage and ensure personnel safety. The input end of the circuit breaker is connected to the secondary output end of the current transformer and receives the current signal from the motor. When an abnormal current is detected, the circuit breaker will automatically disconnect, cutting off the connection between the motor and the power supply, thus achieving the function of protecting the motor. The circuit breaker will monitor this current and compare it with a preset threshold (such as overload current, short-circuit current, etc.). If the monitored current exceeds the preset threshold, the circuit breaker will trigger an action to disconnect the circuit to protect the motor and other equipment from damage.

[0029] In some embodiments, the low-voltage reactor can be selected as the ACL-200 series low-voltage reactor. When connected in series with a capacitor, the reactor can limit the inrush current generated during capacitor switching and protect the capacitor and switchgear from excessive current impact. As part of the reactive power compensation device, it cooperates with the capacitor to form a tuned filter, which is used to absorb harmonic currents of specific frequencies, while providing the necessary reactive power support to improve the power factor of the power grid. The low-voltage reactor can also be used to limit the short-circuit current during short-circuit faults, protecting power equipment and system stability. By adjusting the distribution of system reactive power and improving the voltage distribution, especially on long-distance transmission lines, voltage drop can be reduced and voltage stability can be improved. And it can prevent the self-excitation resonance phenomenon that may occur when the generator is connected to a long line, ensuring the safe operation of the generator. It reduces the power frequency transient overvoltage caused by the capacitive effect of no-load or lightly loaded lines and protects motor equipment from overvoltage damage.

[0030] In this embodiment, the transformer includes a step-up transformer, and the step-up transformer can be selected as a three-phase transformer. The transformer also includes a temperature sensor and a gas relay. The temperature sensor is placed on the surface of the transformer and is used to monitor the temperature of the transformer; the gas relay is placed inside the transformer and is used to detect internal faults of the transformer. The temperature sensor is used to monitor the temperature of the transformer to prevent overheating; the gas relay is used to detect internal faults of the transformer, such as gas generated by short circuits, and send signals or cut off the power supply in a timely manner.

[0031] In this embodiment, the current transformer assembly includes a first current transformer and a second current transformer. The windings of the first current transformer and the second current transformer are connected in parallel. The current transformer assembly further includes an overcurrent relay, which is electrically connected to the current transformer assembly. The primary winding of the current transformer is connected in series in the input circuit of the motor, and the primary winding of the current transformer is directly inserted into the power supply line of the motor and connected in series with the motor input terminal. In this way, when the motor is running, its current will flow through the primary winding of the current transformer. Since the current transformer assembly works based on the principle of electromagnetic induction, this current will generate a magnetic field in the primary winding, and then induce a smaller current proportional to the primary current in the secondary winding. The smaller current generated by the secondary winding of the current transformer is sent to the input terminal of the circuit breaker module (or more specifically, to the protection or measurement device associated with the circuit breaker). This smaller current represents the magnitude of the actual current of the motor, but is within a safe and easily measurable range.

[0032] In one of the embodiments, the underwater high-voltage motor further includes a thermal relay, which is connected in series with the high-voltage motor winding. In some embodiments, the underwater high-voltage motor and the primary winding of the current transformer are connected in series to the high-voltage motor circuit, and the current in the motor circuit can be directly measured. However, when installing, the high-voltage circuit needs to be cut off, which takes a long time and poses a greater safety risk. During the installation process, strict insulation treatment must be carried out to ensure that the coil is not in poor contact with the outside to avoid the danger of electric arc and electric shock. The thermal relay is connected in series with the high-voltage motor winding, and the overcurrent relay is added. When the motor current exceeds the set threshold, the overcurrent relay operates to trigger the protection circuit to disconnect the circuit breaker to protect the motor from damage caused by excessive current.

[0033] The underwater high-voltage motor speed regulation system provided in this embodiment inputs a 380V voltage through a three-phase power supply, adjusts the speed through a low-voltage frequency converter, and then passes through a low-voltage reactor. After filtering by the reactor, the 380V voltage is transformed into high voltage by a transformer and transmitted to the high-voltage motor. The function of the high-voltage current transformer is to monitor the current of the motor. When the current is abnormal, the protection circuit will disconnect the low-voltage circuit breaker to protect the motor. The low-voltage reactor is more economical in price and smaller in size, which not only reduces the equipment cost expenditure but also improves the safety of the equipment circuit.

[0034] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A speed control system for an underwater high-voltage motor, characterized in that: The speed regulation system includes a circuit breaker, a frequency converter, a reactor, a transformer, a current transformer assembly and a high-voltage motor connected in series in sequence; wherein the input end of the circuit breaker is connected to a three-phase voltage of 380V; the current transformer assembly includes two high-voltage current transformers configured in parallel.

2. The speed control system of the underwater high-voltage motor according to claim 1, characterized in that: The frequency converter is a low voltage frequency converter, including ACS510 series frequency converter.

3. The speed control system of the underwater high-voltage motor according to claim 1, characterized in that: The reactor is a low-voltage reactor, comprising an adjustable inductance element with an iron core.

4. The speed control system of the underwater high-voltage motor according to claim 3, characterized in that: The low-voltage reactor includes an ACL-200 series low-voltage reactor.

5. The speed control system of the underwater high-voltage motor according to claim 1, characterized in that: The transformer is a step-up transformer, including a three-phase transformer.

6. The speed control system of the underwater high-voltage motor according to claim 1, characterized in that: The transformer further comprises a temperature sensor, which is arranged on the surface of the transformer and is used to monitor the temperature of the transformer.

7. The speed control system of the underwater high-voltage motor according to claim 1, characterized in that: The current transformer further includes an overcurrent relay, and the overcurrent relay is electrically connected to the current transformer module.

8. The speed control system of the underwater high-voltage motor according to claim 1, characterized in that: The high-voltage motor also includes a thermal relay, which is connected in series with the high-voltage motor winding.

9. The speed control system of the underwater high-voltage motor according to claim 1, characterized in that: The transformer further comprises a gas relay, which is arranged inside the transformer and is used for detecting internal faults of the transformer.

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