10kV on-load voltage regulation intelligent transformer

Abstract

The present invention discloses a 10kV on-load voltage regulating intelligent transformer, including a main coil and a voltage regulating coil, and also including a detection unit, a voltage regulating control unit and a voltage regulating execution unit. The detection unit is connected to the main coil and the voltage regulating coil for detecting voltage and current. The voltage regulating control unit performs demand analysis according to the detected voltage and current, and outputs a voltage regulating control signal to the voltage regulating execution unit according to the demand analysis result. The voltage regulating execution unit includes a transition path and a plurality of tapping gears. The voltage regulating execution unit performs transition and switching of the tapping gear according to the received voltage regulating control signal to complete the voltage regulation. The voltage regulating demand can be analyzed, and the voltage can be regulated by using the set plurality of tapping gears, so the judgment of the voltage regulating demand is more accurate.

Description

Technical Field

[0001] The invention relates to the technical field of transformer voltage regulation, and in particular to a 10kV on-load voltage regulation intelligent transformer. Background Art

[0002] In recent years, with the increasing attention paid to power quality in the development of my country's power grid, the focus of power grid development has gradually shifted from "having electricity" to "using electricity well". In addition to ensuring that residential users have access to electricity, ensuring the safety and reliability of residential users' electricity use has gradually become one of the main tasks of power grid development.

[0003] At present, there are a large number of small-scale power stations such as new energy power stations, hydropower stations and small thermal power plants. The self-regulation ability of such power stations is relatively weak. When connected to the grid, they have a greater impact on the voltage fluctuation of the 10kV line, which often leads to large voltage deviations, thereby causing voltage anomalies (high or low voltage) in distribution stations with lower voltage levels.

[0004] At present, the main grid transformers have gradually adopted on-load voltage regulation technology, but the voltage regulation range is usually small, the working efficiency is low, and the voltage regulation demand cannot be accurately judged, resulting in poor voltage regulation effect and unable to meet the voltage regulation demand of distribution transformers, making the output voltage of the transformer still uncontrollable. Summary of the invention

[0005] In view of the problem that the prior art cannot accurately judge the voltage regulation demand, the present invention provides a 10kV on-load voltage regulation intelligent transformer, which can analyze the voltage regulation demand and use multiple tap positions to regulate the voltage, so the judgment of the voltage regulation demand is more accurate.

[0006] The following is the technical solution of the present invention.

[0007] A 10kV on-load voltage-regulating intelligent transformer comprises a main coil and a voltage-regulating coil, and also comprises a detection unit, a voltage-regulating control unit and a voltage-regulating execution unit. The detection unit is connected to the main coil and the voltage-regulating coil for detecting voltage and current. The voltage-regulating control unit performs demand analysis according to the detected voltage and current, and outputs a voltage-regulating control signal to the voltage-regulating execution unit according to the demand analysis result. The voltage-regulating execution unit comprises a transition path and a plurality of tapping gears. The voltage-regulating execution unit performs transition and switching of the tapping gears according to the received voltage-regulating control signal to complete voltage regulation.

[0008] The present invention changes the voltage ratio by increasing or decreasing the turns of the tapped winding through the tapping gear, thereby achieving voltage regulation, and utilizes multiple units to detect various power parameters, judge and analyze the voltage regulation demand, so as to achieve accurate judgment of the current situation and complete precise voltage regulation.

[0009] Preferably, the voltage regulation execution unit further includes: a main path, a first selector and a second selector, the tapping position is formed by connecting a plurality of taps to different positions of the voltage regulating coil, the main path is connected to the fixed end of the first selector, a plurality of switching ends of the first selector are connected to the taps, the transition path is connected to the fixed end of the second selector, a plurality of switching ends of the second selector are connected to the taps. In order to ensure that the current is not interrupted during the voltage regulation process, and to prevent the backflow from being generated during the switching process and causing an inter-electrode short circuit, the present invention designs a transition path.

[0010] Preferably, after receiving the voltage regulation control signal, the voltage regulation execution unit performs the following steps:

[0011] A1: The tap corresponding to the current tap position is used as the first tap, and the tap corresponding to the target tap position is used as the second tap. The second selector connects the transfer end to the first tap, and the transition path changes from the disconnected state to the connected state. A2: The main path changes from the connected state to the disconnected state, so that the transition path temporarily takes over the load of the main path.

[0012] A3: The first selector connects the transfer end to the second tap, and the main path changes from the disconnected state to the connected state;

[0013] A4: The transition path changes from the on state to the off state, the second selector restores the transfer end or connects it to the second tap, and the voltage regulation ends.

[0014] During the voltage regulation process, at least one line is always kept conductive.

[0015] Preferably, the voltage regulation control unit comprises:

[0016] The voltage comparison module is used to record the voltage fluctuation curve in real time according to the detected voltage, and send out a voltage regulation preparation signal when the voltage extreme value deviates from the preset range;

[0017] A load calculation module is used to calculate a load fluctuation curve according to the detected current and voltage, and output the load fluctuation curve to the analysis module when a voltage regulation preparation signal is received;

[0018] The analysis module analyzes and generates a voltage regulation control signal according to the voltage regulation preparation signal, the voltage fluctuation curve and the load fluctuation curve, and outputs the signal to the voltage regulation execution unit.

[0019] Preferably, when the analysis module analyzes and generates the voltage regulation control signal, the following steps are performed:

[0020] B1: Determine the voltage corresponding to the voltage when the voltage regulation preparation signal is issued. If it is higher than the preset range, execute B2; if it is lower than the preset range, execute B3;

[0021] B2: Draw the voltage moving average of the specified period according to the voltage fluctuation curve, and judge whether there is a section that meets the output fluctuation characteristics of the power station before and after the voltage regulation preparation signal is issued. If so, it is considered that the power station output fluctuation occurs and jump to B4, otherwise jump to B5;

[0022] B3: Draw the load average line of the specified period according to the load fluctuation curve, and judge whether there is a continuous rising section of the load average line of the specified period before the voltage regulation preparation signal is issued. If so, it is considered that the load factor causes the voltage to drop, and jump to B6, otherwise jump to B7;

[0023] B4: Outputs a voltage-step-down control signal to reduce the voltage to the middle value of a preset voltage range;

[0024] B5: Output a voltage-step-down control signal to reduce the voltage to the upper limit of the preset voltage range;

[0025] B6: Output boost voltage regulation control signal; boost voltage to the lower limit of the preset voltage range;

[0026] B7: Outputs a voltage-boosting control signal to boost the voltage to the middle value of the preset voltage range;

[0027] When executing the above steps, in the case corresponding to B4, the output fluctuation of the power station usually has a certain degree of continuity, so it is adjusted to the median value to prevent frequent triggering of voltage regulation; in the case corresponding to B5, the voltage increase caused by other factors is usually less continuous, and after dropping to the upper limit value, it will most likely return to near the median value in a short time due to the elimination of the factors; in the case corresponding to B6, the voltage is reduced due to excessive load. If the voltage is greatly increased, it may cause overload and easily cause danger, so the voltage regulation is mainly based on safety; in the case corresponding to B7, in other cases, the voltage regulation is mainly based on voltage stability.

[0028] Preferably, the main passage and the transition passage both include vacuum tubes, and the vacuum tubes are used to control the on-off of the circuit.

[0029] Preferably, the transition path further includes a transition resistor.

[0030] The substantial effects of the present invention include: by analyzing the power parameters, accurate judgment of the voltage regulation demand can be achieved, and then appropriate voltage regulation operation can be obtained to cope with different actual situations, and through the coordination of the main path and the transition path, the current is ensured not to be interrupted during the voltage regulation process, while also preventing the backflow generated during the switching process from causing an inter-electrode short circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the voltage regulation process of an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution will be clearly and completely described below in combination with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be understood that in various embodiments of the present invention, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0034] It should be understood that in the present invention, "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0035] It should be understood that in the present invention, "plurality" refers to two or more than two. "And / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "Contains A, B and C", "Contains A, B, C" means that A, B, and C are all included, "Contains A, B or C" means that one of A, B, and C is included, and "Contains A, B and / or C" means that any one, any two, or any three of A, B, and C are included.

[0036] The technical solution of the present invention is described in detail with specific embodiments below. The embodiments may be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0037] Example:

[0038] A 10kV on-load voltage-regulating intelligent transformer comprises a main coil and a voltage-regulating coil, and also comprises a detection unit, a voltage-regulating control unit and a voltage-regulating execution unit. The detection unit is connected to the main coil and the voltage-regulating coil for detecting voltage and current. The voltage-regulating control unit performs analysis based on the detected voltage and current, and outputs a voltage-regulating control signal to the voltage-regulating execution unit based on the analysis result. The voltage-regulating execution unit comprises a transition path and a plurality of tapping positions. The voltage-regulating execution unit performs transition and switching of the tapping positions based on the received voltage-regulating control signal to complete voltage regulation.

[0039] The tap of this embodiment has 9-speed voltage regulation selection terminals, which are respectively connected to the 9 coil taps on the transformer. When the controller detects a voltage fault on the high-voltage side, it sends out instructions to control the mechanism on the tap to achieve upshift and downshift of the coil voltage.

[0040] The present invention changes the voltage ratio by increasing or decreasing the turns of the tapped winding through the tapping gear, thereby achieving voltage regulation, and utilizes multiple units to detect various power parameters, judge and analyze the voltage regulation demand, so as to achieve accurate judgment of the current situation and complete precise voltage regulation.

[0041] Whether it is a vacuum on-load tap changer or a non-vacuum on-load tap changer, the changes in the transformer can be adjusted by changing the number of turns of the primary or secondary winding. This can usually be achieved through three voltage regulation methods: linear voltage regulation, positive and negative voltage regulation, and coarse and fine voltage regulation.

[0042] Linear voltage regulation: The tap winding is fixed to the main winding. It increases or decreases the turns of the tap winding to change the voltage ratio. It is usually applicable in the medium voltage regulation range. Any tap position can be used as the rated position.

[0043] Positive and negative voltage regulation: The tap winding can be connected to the high-voltage basic winding in the positive or negative direction. The tap winding is half of the entire voltage regulation range. The polarity conversion operation of the tap winding can be realized by configuring a polarity selector in the vacuum on-load tap. Its rated working position is usually in the middle, except for special designs. Positive and negative voltage regulation usually uses a single polarity selector to roughly double the tap range. The polarity selector connects the tap winding to the main winding in a vector addition or subtraction manner, thereby increasing the tap winding voltage regulation range or reducing the number of taps. At this time, the main winding and the tap winding are instantly disconnected, and the entire tap winding is fully connected to the line at the minimum effective number of turns, and the copper loss generated by the transformer is the largest. For large single-phase transformers, a bipolar selector design is sometimes selected.

[0044] Coarse and fine voltage regulation: The tap winding consists of two parts, coarse and fine. The fine winding can be connected in series with the coarse winding and the high-voltage basic winding, or it can be connected only to the high-voltage basic winding. The coarse and fine voltage regulation conversion operation of the tap winding can be realized by configuring a coarse adjustment selector in the vacuum on-load tap changer. The coarse adjustment selector is part of the selector switch or tap selector, and its rated working position is usually in the middle. Coarse and fine voltage regulation generally uses a single coarse adjustment selector, so that the tap winding can be added or subtracted from the coarse adjustment winding to increase or decrease the voltage regulation range. When the coarse adjustment selector is operated, the high-voltage basic winding and the tap winding will be separated instantly, and the copper loss is minimal at the minimum effective number of turns.

[0045] There are three basic voltage regulation methods, each with its own voltage regulation characteristics and applicable scope, and different insulation requirements. Coarse and fine voltage regulation and positive and negative voltage regulation are usually suitable for 220kV larger transformers. The tap winding of linear voltage regulation is always connected in series with the high-voltage basic winding. Compared with positive and negative regulation or coarse and fine regulation, it will not cause problems such as tap winding potential connection and potential suspension. In addition, there is no conversion selector device on the vacuum on-load tap, and the overall structure is relatively simple, which is more suitable for 10kV and 35kV small transformers. Therefore, this embodiment selects linear voltage regulation.

[0046] like Figure 1 As shown, the voltage regulation execution unit includes: a main path, a transition path, a first selector, a second selector and a plurality of taps, wherein the taps are respectively connected to different positions of the voltage regulating coil to form a tapping gear, the main path is connected to the fixed end of the first selector, the plurality of switching ends of the first selector are respectively connected to the taps, the transition path is connected to the fixed end of the second selector, and the plurality of switching ends of the second selector are respectively connected to the taps. In order to ensure that the current is not interrupted during the voltage regulation process and to prevent the backflow from being generated during the switching process and causing an inter-electrode short circuit, the present invention designs a transition path.

[0047] Specifically, the main path includes a vacuum tube K1, and the transition path includes a vacuum tube K2, which is used to control the on and off of the circuit. At the same time, the transition path also includes a transition resistor R. The first selector is a single isolation conversion contact K3, and the second selector is a single isolation conversion contact K4.

[0048] Figure 1 The complete process of a voltage regulation process is shown. After the voltage regulation execution unit receives the voltage regulation control signal, it performs the following steps:

[0049] A1: The tap corresponding to the current tap position is used as the first tap, and the tap corresponding to the target tap position is used as the second tap. The second selector connects the transfer end to the first tap, and the transition path changes from the disconnected state to the connected state. A2: The main path changes from the connected state to the disconnected state, so that the transition path temporarily takes over the load of the main path.

[0050] A3: The first selector connects the transfer end to the second tap, and the main path changes from the disconnected state to the connected state;

[0051] A4: The transition path changes from the on state to the off state, the second selector restores the transfer end or connects it to the second tap, and the voltage regulation ends.

[0052] During the voltage regulation process, at least one line is always kept conductive.

[0053] The voltage regulation control unit of this embodiment includes:

[0054] The voltage comparison module is used to record the voltage fluctuation curve in real time according to the detected voltage, and send out a voltage regulation preparation signal when the voltage extreme value deviates from the preset range;

[0055] A load calculation module is used to calculate a load fluctuation curve according to the detected current and voltage, and output the load fluctuation curve to the analysis module when a voltage regulation preparation signal is received;

[0056] The analysis module analyzes and generates a voltage regulation control signal according to the voltage regulation preparation signal, the voltage fluctuation curve and the load fluctuation curve, and outputs the signal to the voltage regulation execution unit.

[0057] When the analysis module analyzes and generates the voltage regulation control signal, the following steps are performed:

[0058] B1: Determine the voltage corresponding to the voltage when the voltage regulation preparation signal is issued. If it is higher than the preset range, execute B2; if it is lower than the preset range, execute B3;

[0059] B2: Draw the voltage moving average of the specified period according to the voltage fluctuation curve, and judge whether there is a section that meets the output fluctuation characteristics of the power station before and after the voltage regulation preparation signal is issued. If so, it is considered that the power station output fluctuation occurs and jump to B4, otherwise jump to B5; the power station output fluctuation characteristics are obtained by the model after a large number of sample training;

[0060] B3: Draw the load average line of the specified period according to the load fluctuation curve, and judge whether there is a continuous rising section of the load average line of the specified period before the voltage regulation preparation signal is issued. If so, it is considered that the load factor causes the voltage to drop, and jump to B6, otherwise jump to B7;

[0061] B4: Outputs a voltage-step-down control signal to reduce the voltage to the middle value of a preset voltage range;

[0062] B5: Output a voltage-step-down control signal to reduce the voltage to the upper limit of the preset voltage range;

[0063] B6: Output boost voltage regulation control signal; boost voltage to the lower limit of the preset voltage range;

[0064] B7: Outputs a voltage-boosting control signal to boost the voltage to the middle value of the preset voltage range;

[0065] When executing the above steps, in the case corresponding to B4, the output fluctuation of the power station usually has a certain degree of continuity, so it is adjusted to the median value to prevent frequent triggering of voltage regulation; in the case corresponding to B5, the voltage increase caused by other factors is usually less continuous, and after dropping to the upper limit value, it will most likely return to near the median value in a short time due to the elimination of the factors; in the case corresponding to B6, the voltage is reduced due to excessive load. If the voltage is greatly increased, it may cause overload and easily cause danger, so the voltage regulation is mainly based on safety; in the case corresponding to B7, in other cases, the voltage regulation is mainly based on voltage stability.

[0066] When small-scale power stations such as new energy power stations, hydropower stations and small thermal power plants are connected to the power grid, causing large voltage fluctuations on 10kV transmission lines, voltage regulation operations should be performed in a timely manner; however, short-term overvoltages may sometimes occur on transmission lines, such as: load input or output in the line, direct lightning or induced lightning strikes on the transmission line, which will cause overvoltages. Such overvoltages are short-lived, and the amplitude of voltage regulation operations can be reduced. In order to achieve reliable voltage regulation of the transformer, precise control of voltage regulation under line voltage fluctuations is required.

[0067] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the specific device can be divided into different functional modules to complete all or part of the functions described above.

[0068] In the embodiments provided in the present application, it should be understood that the disclosed structures and methods can be implemented in other ways. For example, the embodiments of the structure described above are only schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another structure, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, structures or units, which can be electrical, mechanical or other forms.

[0069] The units described as separate components may or may not be physically separated, and the components shown as units may be one physical unit or multiple physical units, that is, they may be located in one place or distributed in multiple different places. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0070] In addition, each functional unit in the embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0071] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium, including several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to perform all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program code.

[0072] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. 10kV on-load voltage regulating intelligent transformer, including main coil and voltage regulating coil, characterized in that: It also includes a detection unit, a voltage regulation control unit and a voltage regulation execution unit. The detection unit is connected to the main coil and the voltage regulation coil to detect voltage and current. The voltage regulation control unit performs demand analysis according to the detected voltage and current, and outputs a voltage regulation control signal to the voltage regulation execution unit according to the demand analysis result. The voltage regulation execution unit includes a transition path and a plurality of tapping gears. The voltage regulation execution unit performs transition and switching of the tapping gear according to the received voltage regulation control signal to complete voltage regulation. The voltage regulation execution unit further includes: a main path, a first selector and a second selector, wherein the tapping positions are formed by connecting a plurality of taps to different positions of the voltage regulation coil, the main path is connected to a fixed end of the first selector, a plurality of adapter ends of the first selector are connected to the taps, the transition path is connected to a fixed end of the second selector, and a plurality of adapter ends of the second selector are connected to the taps; After receiving the voltage regulation control signal, the voltage regulation execution unit executes the following steps: A1: The tap corresponding to the current tap position is used as the first tap, and the tap corresponding to the target tap position is used as the second tap. The second selector connects the transfer end to the first tap, and the transition path changes from the disconnected state to the conductive state. A2: The main path changes from the on state to the off state, so that the transition path temporarily takes over the load of the main path; A3: The first selector connects the transfer end to the second tap, and the main path changes from the disconnected state to the connected state; A4: The transition path changes from the on state to the off state, the second selector restores the transfer end or connects it to the second tap, and the voltage regulation ends; The voltage regulation control unit comprises: The voltage comparison module is used to record the voltage fluctuation curve in real time according to the detected voltage, and send out a voltage regulation preparation signal when the voltage extreme value deviates from the preset range; A load calculation module is used to calculate a load fluctuation curve according to the detected current and voltage, and output the load fluctuation curve to the analysis module when a voltage regulation preparation signal is received; The analysis module analyzes and generates a voltage regulation control signal according to the voltage regulation preparation signal, the voltage fluctuation curve and the load fluctuation curve, and outputs the signal to the voltage regulation execution unit.

2. The 10kV on-load voltage-changing intelligent transformer according to claim 1 is characterized in that: When the analysis module analyzes and generates the voltage regulation control signal, the following steps are performed: B1: Determine the voltage corresponding to the voltage when the voltage regulation preparation signal is issued. If it is higher than the preset range, execute B2; if it is lower than the preset range, execute B3; B2: Draw the voltage moving average of the specified period according to the voltage fluctuation curve, and judge whether there is a section that meets the output fluctuation characteristics of the power station before and after the voltage regulation preparation signal is issued. If so, it is considered that the power station output fluctuation occurs and jump to B4, otherwise jump to B5; B3: Draw the load average line of the specified period according to the load fluctuation curve, and judge whether there is a continuous rising section of the load average line of the specified period before the voltage regulation preparation signal is issued. If so, it is considered that the load factor causes the voltage to drop, and jump to B6, otherwise jump to B7; B4: Outputs a voltage-step-down control signal to reduce the voltage to the middle value of a preset voltage range; B5: Output a voltage-step-down control signal to reduce the voltage to the upper limit of the preset voltage range; B6: Output boost voltage regulation control signal; boost voltage to the lower limit of the preset voltage range; B7: Outputs a voltage regulation control signal for boosting the voltage to the middle value of the preset voltage range.

3. The 10kV on-load voltage-changing intelligent transformer according to claim 1 is characterized in that: The main passage and the transition passage both include vacuum tubes, and the vacuum tubes are used to control the on and off of the circuits.

4. The 10kV on-load voltage-changing intelligent transformer according to claim 3 is characterized in that: The transition path also includes a transition resistor.

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