Distribution transformer and detection method, system and control method of voltage regulation ratio thereof

Abstract

The present invention relates to a detection method for the voltage regulation ratio of a distribution transformer, comprising the following steps: calculating the initial voltage regulation ratio of the distribution transformer according to the primary input voltage amplitude, the secondary current amplitude and the secondary current phase value of the distribution transformer; obtaining the voltage deviation value according to the voltage standard value and the instantaneous effective value of the secondary output voltage of the distribution transformer; if the voltage deviation value exceeds the preset voltage deviation threshold, obtaining the difference between the voltage deviation value and the preset voltage deviation threshold; integrating the difference to obtain the integral value, compensating the initial distribution transformer voltage regulation ratio according to the integral value to obtain the distribution transformer voltage regulation ratio. The above method improves the switching speed and accuracy of the voltage regulation ratio of the distribution transformer, can quickly and accurately control the power electronic switch, effectively adjust the output voltage of the distribution transformer, and provides a basis for the design of the power electronic on-load voltage regulation distribution transformer.

Description

Technical Field

[0001] The present invention relates to the technical field of on-load voltage-regulating distribution transformers, and in particular to a method and system for detecting a voltage-regulating ratio of a distribution transformer, a control method for a distribution transformer, and a voltage-regulating distribution transformer. Background Art

[0002] The low voltage problem in the distribution network seriously affects the safe and economical operation of equipment and the high-quality and reliable power supply to users, and has become one of the problems that need to be solved urgently in the distribution network. When the compensation capacity of the power grid is sufficient, solving the low voltage problem in the distribution network requires solving the problem of voltage and reactive power control. The on-load voltage regulation of the distribution transformer is an effective voltage and reactive power regulation measure. Therefore, by installing an on-load voltage regulation distribution transformer, the voltage and reactive power regulation capacity of the distribution network can be improved, thereby solving the low voltage problem of the distribution network.

[0003] Nowadays, power electronic on-load voltage-regulating distribution transformers use power electronic switches to completely replace mechanical contact switches. By controlling the on and off of power electronic switches, the on-load voltage regulation of distribution transformers is achieved, which has the advantages of switching without arcing, fast action rate and long service life. The voltage regulation ratio of the distribution transformer can be used to control the on and off of the power electronic switch. However, in traditional technologies, the voltage regulation ratio in the distribution transformer has a slow switching speed and low accuracy, which makes it difficult to meet the requirements of the power electronic switch for the speed and accuracy of the control signal, hindering the development of power electronic on-load voltage-regulating distribution transformers. Summary of the invention

[0004] Based on this, it is necessary to provide a method and system for detecting the voltage regulation ratio of a distribution transformer, a control method for a distribution transformer, and a voltage regulating distribution transformer to address the problems of slow switching and low accuracy of the voltage regulation ratio in the distribution transformer.

[0005] A method for detecting a voltage regulation ratio of a distribution transformer comprises the following steps:

[0006] Calculate the initial distribution transformer voltage regulation ratio according to the primary side input voltage amplitude, secondary side current amplitude and secondary side current phase value of the distribution transformer;

[0007] Obtaining a voltage deviation value according to a voltage standard value and an instantaneous effective value of a secondary-side output voltage of the distribution transformer;

[0008] If the voltage deviation value exceeds a preset voltage deviation threshold, obtaining a difference between the voltage deviation value and the preset voltage deviation threshold;

[0009] The difference is integrated to obtain an integral value, and the initial distribution transformer voltage regulation ratio is compensated according to the integral value to obtain the distribution transformer voltage regulation ratio.

[0010] The above-mentioned detection method of the voltage regulation ratio of the distribution transformer adjusts the voltage regulation ratio of the distribution transformer in real time according to the difference between the voltage deviation value and the preset voltage deviation threshold value, improves the switching speed and accuracy of the voltage regulation ratio of the distribution transformer, meets the requirements of the power electronic switch for speed and accuracy, and can quickly and accurately control the power electronic switch according to the voltage regulation ratio, effectively adjust the output voltage of the distribution transformer, and provide a basis for the design of power electronic on-load voltage regulation distribution transformer.

[0011] In one embodiment, after the step of obtaining the voltage deviation value according to the voltage standard value and the instantaneous effective value of the secondary side output voltage of the distribution transformer, the following steps are also included:

[0012] If the voltage deviation value is within the preset voltage deviation threshold, the current actual transformation ratio of the distribution transformer is used as the voltage regulation transformation ratio of the distribution transformer.

[0013] In one embodiment, the step of calculating the initial distribution transformer voltage regulation ratio according to the primary side input voltage amplitude, the secondary side current amplitude and the secondary side current phase value of the distribution transformer comprises the following steps:

[0014] Establishing a distribution transformer model according to the primary and secondary side circuit structure of the distribution transformer, and obtaining a distribution transformer voltage regulation ratio calculation model according to the distribution transformer model;

[0015] The initial distribution transformer voltage regulation ratio is calculated according to the distribution transformer voltage regulation ratio calculation model using the primary side input voltage amplitude, secondary side current amplitude and secondary side current phase value of the distribution transformer.

[0016] In one embodiment, the distribution transformer voltage regulation ratio calculation model is as follows:

[0017]

[0018] Among them, V ref is the voltage standard value, V1 is the primary input voltage amplitude of the distribution transformer, I2 and θ I are the secondary current amplitude and phase of the distribution transformer, Z and θ Z are the magnitude and phase of the total impedance of the circuit, respectively.

[0019] In one embodiment, the method for detecting the voltage regulation ratio of the distribution transformer further includes the following steps:

[0020] Obtaining the fundamental component and harmonic component of the secondary side output voltage;

[0021] The instantaneous effective value of the secondary side output voltage of the distribution transformer is calculated using a numerical matrix according to the fundamental component and the harmonic component of the secondary side output voltage.

[0022] In one embodiment, the method for detecting the voltage regulation ratio of the distribution transformer further includes the following steps:

[0023] Obtain the rated transformation ratio of the distribution transformer, the difference in transformation ratios between adjacent taps, the maximum amplitude of the primary voltage of the distribution transformer, and the maximum number of taps;

[0024] The preset voltage deviation threshold is calculated according to the following formula using the rated transformation ratio of the distribution transformer, the transformation ratio difference of adjacent taps, the maximum amplitude of the primary side voltage of the distribution transformer, and the maximum number of taps:

[0025]

[0026] Among them, V 1max is the maximum voltage amplitude of the primary side of the distribution transformer, a0 is the initial voltage regulation ratio of the distribution transformer, △a is the ratio difference of adjacent taps, n max is the maximum number of taps.

[0027] A detection system for a voltage regulation ratio of a distribution transformer, comprising:

[0028] A voltage regulation ratio acquisition module is used to calculate the initial distribution transformer voltage regulation ratio according to the primary side input voltage amplitude, secondary side current amplitude and secondary side current phase value of the distribution transformer;

[0029] A voltage deviation value acquisition module, used to acquire a voltage deviation value according to a voltage standard value and an instantaneous effective value of a secondary side output voltage of the distribution transformer;

[0030] A voltage regulation judgment module, configured to obtain a difference between the voltage deviation value and the preset voltage deviation threshold value if the voltage deviation value exceeds the preset voltage deviation threshold value;

[0031] The voltage regulation ratio compensation module is used to integrate the difference to obtain an integral value, and compensate the initial distribution transformer voltage regulation ratio according to the integral value to obtain the distribution transformer voltage regulation ratio.

[0032] The above-mentioned distribution transformer voltage regulation ratio detection system adjusts the distribution transformer voltage regulation ratio in real time according to the difference between the voltage deviation value and the preset voltage deviation threshold, and quickly and accurately controls the power electronic switch according to the voltage regulation ratio, meeting the requirements of power electronic switch switching for speed and accuracy, and can effectively adjust the output voltage of the distribution transformer, providing a basis for the design of power electronic on-load voltage regulation distribution transformer.

[0033] A control method for a distribution transformer comprises the following steps:

[0034] Detecting the voltage regulation ratio of the distribution transformer using the above-mentioned detection method of the voltage regulation ratio of the distribution transformer;

[0035] The on-off of the power electronic switch in the distribution transformer is controlled according to the voltage regulation ratio of the distribution transformer to switch the tap.

[0036] The control method of the distribution transformer mentioned above realizes the switching of taps by obtaining the voltage regulation ratio of the distribution transformer to control the on and off of the power electronic switch, wherein the voltage regulation ratio of the distribution transformer is adjusted according to the actual situation of the circuit, and the switching speed and accuracy of the voltage regulation ratio of the distribution transformer are improved, which meets the requirements of the power electronic switch for speed and accuracy, and can quickly and accurately control the power electronic switch, so that the distribution transformer can effectively adjust the output voltage of the distribution transformer.

[0037] In one embodiment, the step of controlling the on and off of the power electronic switch in the distribution transformer according to the transformation ratio of the distribution transformer and switching the tap comprises the following steps:

[0038] If the primary side voltage amplitude reaches zero, digitally convert the voltage regulation ratio of the distribution transformer to obtain the tap ratio of the distribution transformer;

[0039] The on and off of the power electronic switch in the distribution transformer is controlled according to the tap ratio to switch the tap.

[0040] A distribution transformer comprises a power electronic on-load voltage regulating distribution transformer and a distribution transformer voltage regulating ratio controller, wherein the distribution transformer voltage regulating ratio controls the power electronic on-load voltage regulating distribution transformer switching tap by using the above-mentioned distribution transformer control method.

[0041] The above-mentioned distribution transformer obtains the voltage regulation ratio of the distribution transformer through the distribution transformer voltage regulation ratio controller to control the on-off of the power electronic switch in the power electronic on-load voltage regulation distribution transformer, thereby realizing the switching of the taps of the power electronic on-load voltage regulation distribution transformer. Among them, the voltage regulation ratio of the distribution transformer is adjusted according to the actual situation of the circuit, and the switching speed and accuracy of the voltage regulation ratio of the distribution transformer are improved, which meets the requirements of the power electronic switch for speed and accuracy, and can quickly and accurately control the power electronic switch, so that the on-load voltage regulation distribution transformer can effectively adjust the output voltage of the distribution transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a flow chart of a method for detecting the voltage regulation ratio of a distribution transformer in one embodiment of the present invention;

[0043] Figure 2 A model diagram of a high-voltage distribution transformer in one embodiment of the present invention;

[0044] Figure 3 It is a structural schematic diagram of a detection system for the voltage regulation ratio of a distribution transformer in one embodiment of the present invention;

[0045] Figure 4 A diagram showing the relationship between the voltage regulation ratio and the tap ratio of a distribution transformer in one embodiment of the present invention;

[0046] Figure 5 A schematic diagram of the structure of a distribution transformer according to an embodiment of the present invention;

[0047] Figure 6 A schematic structural diagram of a distribution transformer according to another embodiment of the present invention;

[0048] Figure 7 This is an output-input relationship diagram of a voltage regulation judgment module in a distribution transformer according to another embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0050] See also Figure 1 , Figure 1 The flowchart of a method for detecting a voltage regulation ratio of a distribution transformer in one embodiment of the present invention is as follows. The method for detecting a voltage regulation ratio of a distribution transformer in this embodiment comprises the following steps:

[0051] Step S110: Calculate the initial distribution transformer voltage regulation ratio according to the primary side input voltage amplitude, secondary side current amplitude and secondary side current phase value of the distribution transformer.

[0052] In this step, the distribution transformer is generally composed of an iron core and a coil. The coil has two or more windings, the primary side is the winding connected to the power supply, and the secondary side is the remaining windings.

[0053] Step S120: obtaining a voltage deviation value according to the voltage standard value and the instantaneous effective value of the secondary side output voltage of the distribution transformer.

[0054] Step S130: if the voltage deviation value exceeds the preset voltage deviation threshold, then obtaining a difference between the voltage deviation value and the preset voltage deviation threshold.

[0055] Step S140: Integrate the difference to obtain an integral value, and compensate the initial distribution transformer voltage regulation ratio according to the integral value to obtain the distribution transformer voltage regulation ratio.

[0056] In this embodiment, the voltage regulation ratio of the distribution transformer is adjusted in real time according to the difference between the voltage deviation value and the preset voltage deviation threshold value, so as to improve the switching speed and accuracy of the voltage regulation ratio of the distribution transformer and meet the requirements of the power electronic switch for speed and accuracy. The power electronic switch can be controlled quickly and accurately according to the voltage regulation ratio of the distribution transformer, and the output voltage of the distribution transformer is effectively adjusted, which provides a basis for the design of the power electronic on-load voltage regulation distribution transformer.

[0057] Specifically, the initial transformer voltage regulation ratio can be calculated based on the primary input voltage amplitude of the distribution transformer, the secondary current amplitude and phase of the distribution transformer. Considering that the circuit resistance and the primary input voltage are set to fixed values ​​when calculating the distribution transformer voltage regulation ratio, the actual distribution transformer circuit resistance and the primary input voltage are constantly changing, which may make the initial distribution transformer voltage regulation ratio not necessarily able to adjust the secondary output voltage of the distribution transformer to the voltage standard value, and a compensation value needs to be introduced.

[0058] Since the taps of the distribution transformer are discontinuous, in order to ensure that the voltage deviation after voltage regulation is lower than the voltage deviation before voltage regulation, the voltage regulation judgment needs to be made according to the output voltage deviation of the secondary side of the distribution transformer. First, the voltage deviation △V is obtained by the voltage standard value and the instantaneous effective value of the output voltage of the secondary side of the distribution transformer. When the voltage deviation value △V exceeds the preset voltage deviation threshold DB, the difference △V-DB between the output voltage deviation value and the preset voltage deviation threshold is output to the integrator. After integrating the difference, the integral value is used to compensate the initial distribution transformer voltage regulation ratio; wherein, by integrating the difference between the voltage deviation value and the preset voltage deviation threshold, the integral value is used to compensate the voltage regulation ratio, which can reduce the delay of the distribution transformer voltage regulation ratio detection and improve the switching speed of the distribution transformer voltage regulation ratio.

[0059] In one embodiment, after the step of obtaining the voltage deviation value according to the voltage standard value and the instantaneous effective value of the secondary side output voltage of the distribution transformer, the following steps are also included:

[0060] If the voltage deviation value is within the preset voltage deviation threshold, the current actual transformation ratio of the distribution transformer is used as the voltage regulation transformation ratio of the distribution transformer.

[0061] In this embodiment, when the voltage deviation value △V is within the range of the preset voltage deviation threshold DB, the current actual transformation ratio of the distribution transformer is used as the voltage regulation ratio of the distribution transformer to ensure that the voltage deviation is minimized, that is, to ensure that the secondary side output voltage of the distribution transformer is close to the voltage standard value, thereby improving the accuracy of the voltage regulation ratio of the distribution transformer, being able to accurately control the power electronic switch according to the voltage regulation ratio, effectively adjusting the output voltage of the distribution transformer, and preventing the occurrence of low voltage problems in the distribution network.

[0062] In one embodiment, the step of calculating the initial distribution transformer voltage regulation ratio according to the primary side input voltage amplitude, the secondary side current amplitude and the secondary side current phase value of the distribution transformer comprises the following steps:

[0063] A distribution transformer model is established according to the primary and secondary circuit structures of the distribution transformer, and a calculation model for the voltage regulation ratio of the distribution transformer is obtained according to the distribution transformer model;

[0064] The initial distribution transformer voltage regulation ratio is calculated according to the distribution transformer voltage regulation ratio calculation model using the primary side input voltage amplitude, secondary side current amplitude and secondary side current phase value of the distribution transformer.

[0065] In this embodiment, by establishing a distribution transformer voltage regulation ratio calculation model, the corresponding distribution transformer voltage regulation ratio can be output after the collected voltage and current data are input, making the calculation process simple and fast.

[0066] Specifically, according to the primary and secondary circuit structure of the distribution transformer, the secondary output voltage of the distribution transformer can be obtained as shown in the following formula:

[0067]

[0068] in, is the transformer secondary output voltage, is the primary input voltage of the transformer, a is the transformer ratio, a min is the minimum transformation ratio of the transformer, a max is the maximum transformation ratio of the transformer, is the transformer secondary current, Z T is the sum of the transformer winding impedance, Z C is the sum of the transmission line impedance between the voltage regulating bus and the transformer. Therefore, the voltage distribution transformer model is established. Figure 2 The function of the distribution transformer is to quickly adjust the output voltage of the secondary side of the distribution transformer to the standard value. Therefore, the voltage standard value is used as the secondary side output voltage of the transformer to obtain the calculation model of the voltage regulation ratio of the distribution transformer.

[0069] In one embodiment, the calculation model of the voltage regulation ratio of the distribution transformer is as follows:

[0070]

[0071] Among them, V ref is the voltage standard value, V1 is the primary input voltage amplitude of the distribution transformer, I2 and θ I are the secondary current amplitude and phase of the distribution transformer, Z and θ Z are the magnitude and phase of the total impedance of the circuit, respectively.

[0072] Specifically, the voltage standard value V ref As the transformer secondary output voltage, according to The calculation model of the voltage regulation ratio of the distribution transformer can be obtained as shown in the above formula.

[0073] In one embodiment, the instantaneous effective value of the secondary side output voltage can be obtained according to the following steps:

[0074] Obtaining the fundamental component and harmonic component of the secondary side output voltage;

[0075] The instantaneous effective value of the secondary side output voltage of the distribution transformer is calculated using a numerical matrix according to the fundamental component and harmonic component of the secondary side output voltage.

[0076] In this embodiment, the fundamental component and the harmonic component of the secondary side output voltage are obtained, and the instantaneous effective value can be calculated through a numerical matrix.

[0077] Specifically, the measured value of the secondary output voltage of the distribution transformer is composed of a fundamental component and multiple harmonic components. In this example, the fundamental component and the fifth harmonic component are considered, so the secondary output voltage of the distribution transformer can be expressed as:

[0078]

[0079] Among them, |u1|, ω1, θ1 are the amplitude, angular frequency and initial phase of the fundamental component, ω1 is 50 Hz, |u5|, ω5, θ5 are the amplitude, angular frequency and initial phase of the 5th harmonic component, ω5 is 250 Hz, and t is the sampling time, T s is the sampling period, u present is the voltage amplitude at sampling time t, u past1 Yes(tT s ) voltage amplitude at time, u past2 Yes (t-2T s ) voltage amplitude at time, u past3 Yes (t-3T s ) time. The numerical matrix method is used to solve the amplitude and phase of the fundamental component and the fifth harmonic component, as shown in equations (4) and (5):

[0080]

[0081]

[0082] According to the four sampling points of the output voltage of the distribution transformer, the instantaneous effective value of the output voltage V can be obtained. 2m for:

[0083]

[0084] From the above calculation formula, it can be seen that the introduction of a harmonic component will add two unknown parameters (amplitude and phase). Therefore, if one more harmonic component is considered, two more sampling points will be needed to calculate the instantaneous effective value of the secondary output voltage of the distribution transformer. In actual application, the number of harmonic components is set according to the accuracy requirements of the instantaneous effective value of the voltage and the calculation speed requirements.

[0085] In one embodiment, the voltage deviation threshold can be obtained by the following steps:

[0086] Obtain the rated transformation ratio of the distribution transformer, the difference in transformation ratios between adjacent taps, the maximum amplitude of the primary voltage of the distribution transformer, and the maximum number of taps;

[0087] The preset voltage deviation threshold is calculated according to the following formula using the rated transformation ratio of the distribution transformer, the transformation ratio difference of adjacent taps, the maximum amplitude of the primary voltage of the distribution transformer, and the maximum number of taps:

[0088]

[0089] Among them, V 1max is the maximum voltage on the primary side of the distribution transformer, a0 is the rated transformation ratio of the distribution transformer, △a is the transformation ratio difference between adjacent taps, and n max is the maximum number of taps.

[0090] In this embodiment, since the taps of the distribution transformer are discontinuous, in order to ensure that the voltage deviation after voltage regulation is lower than the voltage deviation before voltage regulation, it is necessary to compare and judge based on the output voltage deviation of the secondary side of the distribution transformer and the voltage deviation threshold. If the voltage deviation is too small, the voltage regulation ratio of the distribution transformer may not be compensated and modulated to improve the accuracy of the voltage regulation ratio of the distribution transformer.

[0091] Specifically, a transformer has multiple windings connected in series, and the leads connected to the connection points of the series windings are called taps. The ratio difference between adjacent taps is constant, so the value range of the voltage deviation threshold is obtained based on data such as the rated ratio of the distribution transformer, the ratio difference between adjacent taps, the maximum amplitude of the primary side voltage of the distribution transformer, and the maximum number of taps. In actual applications, an appropriate value is selected based on the value range as the preset voltage deviation threshold.

[0092] According to the above-mentioned method for detecting the voltage regulation ratio of a distribution transformer, the present invention further provides a system for detecting the voltage regulation ratio of a distribution transformer. The embodiment of the system for detecting the voltage regulation ratio of a distribution transformer of the present invention is described in detail below.

[0093] See also Figure 3 , Figure 3The structure diagram of the detection system of the voltage regulation ratio of the distribution transformer in one embodiment of the present invention is shown in FIG. In this embodiment, the detection system of the voltage regulation ratio of the distribution transformer includes:

[0094] A voltage regulation ratio acquisition module 210 is used to calculate an initial distribution transformer voltage regulation ratio according to a primary-side input voltage amplitude, a secondary-side current amplitude, and a secondary-side current phase value of the distribution transformer;

[0095] A voltage deviation value acquisition module 220 is used to acquire a voltage deviation value according to a voltage standard value and an instantaneous effective value of a secondary side output voltage of a distribution transformer;

[0096] The voltage adjustment judgment module 230 is used to obtain the difference between the voltage deviation value and the preset voltage deviation threshold value if the voltage deviation value exceeds the preset voltage deviation threshold value;

[0097] The voltage regulation ratio compensation module 240 is used to integrate the difference to obtain an integral value, and to compensate the initial distribution transformer voltage regulation ratio according to the integral value to obtain the distribution transformer voltage regulation ratio.

[0098] In this embodiment, the voltage regulation ratio of the distribution transformer is adjusted in real time according to the difference between the voltage deviation value and the preset voltage deviation threshold value, and the power electronic switch is quickly and accurately controlled according to the voltage regulation ratio, so as to meet the requirements of the power electronic switch for rapidity and accuracy, and can effectively adjust the output voltage of the distribution transformer, thereby providing a basis for the design of a power electronic on-load voltage regulation distribution transformer.

[0099] In one embodiment, when the voltage deviation value is within a preset voltage deviation threshold, the voltage regulation judgment module 230 uses the current actual transformation ratio of the distribution transformer as the voltage regulation transformation ratio of the distribution transformer.

[0100] In one of the embodiments, the voltage regulation ratio acquisition module 210 establishes a distribution transformer model according to the primary and secondary side circuit structures of the distribution transformer, and acquires a distribution transformer voltage regulation ratio calculation model according to the distribution transformer model; and calculates the distribution transformer voltage regulation ratio according to the distribution transformer voltage regulation ratio calculation model using the primary side input voltage amplitude, secondary side current amplitude, and secondary side current phase value of the distribution transformer.

[0101] In one embodiment, the calculation model of the voltage regulation ratio of the distribution transformer in the voltage regulation ratio acquisition module 210 is as follows:

[0102]

[0103] Among them, V ref is the voltage standard value, V1 is the primary input voltage amplitude of the distribution transformer, I2 and θ I are the secondary current amplitude and phase of the distribution transformer, Z and θ Zare the magnitude and phase of the total impedance of the circuit, respectively.

[0104] In one embodiment, the voltage deviation value acquisition module 220 acquires the fundamental component and the harmonic component of the secondary side output voltage; and calculates the instantaneous effective value of the secondary side output voltage of the distribution transformer using a numerical matrix according to the fundamental component and the harmonic component of the secondary side output voltage.

[0105] In one embodiment, the voltage regulation judgment module 230 obtains the rated transformation ratio of the distribution transformer, the difference between adjacent tap ratios, the maximum amplitude of the primary side voltage of the distribution transformer, and the maximum number of taps; and calculates the preset voltage deviation threshold according to the following formula using the rated transformation ratio of the distribution transformer, the difference between adjacent tap ratios, the maximum amplitude of the primary side voltage of the distribution transformer, and the maximum number of taps:

[0106]

[0107] Among them, V 1max is the maximum voltage on the primary side of the distribution transformer, a0 is the rated transformation ratio of the distribution transformer, △a is the transformation ratio difference between adjacent taps, n max is the maximum number of taps.

[0108] The detection system of the voltage regulation ratio of the distribution transformer of the present invention corresponds one to one with the detection method of the voltage regulation ratio of the distribution transformer of the present invention. The technical features and beneficial effects described in the embodiment of the detection method of the voltage regulation ratio of the distribution transformer are applicable to the embodiment of the detection system of the voltage regulation ratio of the distribution transformer, and this is hereby declared.

[0109] In one embodiment, the present invention further provides a control method for a distribution transformer, the control method for a distribution transformer comprising the following steps:

[0110] Detecting the voltage regulation ratio of the distribution transformer using any of the above-mentioned detection methods for the voltage regulation ratio of the distribution transformer;

[0111] The on and off of the power electronic switch in the distribution transformer is controlled according to the voltage regulation ratio of the distribution transformer to switch the tap.

[0112] In this embodiment, the tap switching is achieved by obtaining the voltage regulation ratio of the distribution transformer to control the on and off of the power electronic switch, wherein the voltage regulation ratio of the distribution transformer is adjusted according to the actual circuit conditions, and the switching speed and accuracy of the voltage regulation ratio of the distribution transformer are improved, meeting the requirements of the power electronic switch for speed and accuracy, and being able to quickly and accurately control the power electronic switch, so that the distribution transformer can effectively adjust the output voltage of the distribution transformer.

[0113] In one embodiment, the step of controlling the on and off of the power electronic switch in the distribution transformer according to the transformation ratio of the distribution transformer and switching the tap includes the following steps:

[0114] If the primary side voltage amplitude reaches zero, the voltage regulation ratio of the distribution transformer is digitally converted to obtain the tap ratio of the distribution transformer;

[0115] The on and off of the power electronic switch in the distribution transformer is controlled according to the tap ratio to switch the taps.

[0116] In this embodiment, the voltage regulation ratio of the distribution transformer is digitally converted to obtain the tap ratio of the distribution transformer, and the on and off of the power electronic switch is controlled according to the tap ratio. The power electronic switch can be controlled quickly and accurately, so that the distribution transformer can effectively regulate the output voltage of the distribution transformer.

[0117] Specifically, since the transformer tap is discontinuous, and the distribution transformer voltage regulation ratio obtained by the detection method of the distribution transformer voltage regulation ratio is a continuous value, it is necessary to digitally convert the obtained distribution transformer voltage regulation ratio to obtain the tap ratio. At the same time, in order to reduce the impact of the tap switching process on the power electronic switch, after obtaining the voltage regulation ratio, the transformer primary side voltage is zero-crossing detected, and when the primary side voltage passes through the zero point, the power electronic switch is controlled to be turned on and off according to the tap ratio to achieve tap switching.

[0118] Furthermore, according to the principle of minimum absolute value of ratio difference, the obtained voltage regulation ratio of the distribution transformer is digitally converted to obtain the tap ratio. The relationship between the voltage regulation ratio of the distribution transformer and the tap ratio is as follows: Figure 4 shown.

[0119] In one embodiment, the present invention also provides a distribution transformer, see Figure 5 , Figure 5 Schematic diagram of the structure of a distribution transformer according to an embodiment of the present invention; the distribution transformer in this embodiment includes a power electronic on-load voltage-regulating distribution transformer 310 and a distribution transformer voltage-regulating ratio controller 320, wherein the distribution transformer voltage-regulating ratio controller 320 controls the power electronic on-load voltage-regulating distribution transformer to switch taps by using the above-mentioned distribution transformer control method.

[0120] In this embodiment, the voltage regulation ratio of the distribution transformer is obtained through the distribution transformer voltage regulation ratio controller 320 to control the on and off of the power electronic switch in the power electronic on-load voltage regulation distribution transformer 310, so as to realize the switching of the taps of the power electronic on-load voltage regulation distribution transformer 310, wherein the voltage regulation ratio of the distribution transformer is adjusted according to the actual circuit conditions, and the switching speed and accuracy of the voltage regulation ratio of the distribution transformer are improved, which meets the requirements of the power electronic switch for speed and accuracy, and can quickly and accurately control the power electronic switch, so that the distribution transformer can effectively adjust the output voltage of the distribution transformer.

[0121] See also Figure 6 , Figure 6 It is a structural schematic diagram of a distribution transformer according to another embodiment of the present invention; in this embodiment, a distribution transformer voltage regulation ratio controller 320 includes a feedforward control module 321, an integration module 322, a voltage regulation judgment module 323, a voltage instantaneous effective value calculation module 324, a sampling and storage module 325, a digital converter module 326 and a zero-crossing detection module 327.

[0122] Among them, according to the primary and secondary side circuit structure of the distribution transformer, the secondary side output voltage of the distribution transformer can be obtained as shown in the following formula:

[0123]

[0124] in, is the transformer secondary output voltage, is the primary input voltage of the transformer, a is the transformer ratio, a min is the minimum transformation ratio of the transformer, a max is the maximum transformation ratio of the transformer, is the transformer secondary current, Z T is the sum of the transformer winding impedance, Z C The function of the distribution transformer is to quickly adjust the secondary output voltage of the distribution transformer to the standard value. Then, the voltage standard value is used as the secondary output voltage of the transformer. The calculation model of the voltage regulation ratio of the distribution transformer can be obtained as shown in the following formula (9), and the calculation model is used as the calculation formula of the feedforward control module 321.

[0125]

[0126] Among them, V ref is the voltage standard value, V1 is the primary input voltage amplitude of the distribution transformer, I2 and θ I are the secondary current amplitude and phase of the distribution transformer, Z and θ Z are the magnitude and phase of the total impedance of the circuit, respectively.

[0127] Input transformer primary side input voltage amplitude V1, transformer secondary side current amplitude I2 and phase value θ I To the feedforward control module 321, output the initial transformer voltage regulation ratio a.

[0128] Taking into account the error introduced by assuming that the circuit resistance is a constant when calculating the voltage regulation ratio of the distribution transformer and the measurement error of the input voltage V1, an integral module 322 is introduced to compensate based on the output of the feedforward control module 321, where the gain of the integral module 322 is determined by system simulation.

[0129] Since the taps of the distribution transformer are discontinuous, in order to ensure that the voltage deviation after voltage regulation is lower than the voltage deviation before voltage regulation, the voltage regulation judgment module 323 is required to perform voltage regulation judgment on the output voltage deviation of the distribution transformer. ref The instantaneous effective value V of the secondary output voltage of the distribution transformer calculated by the voltage instantaneous effective value calculation module 324 2m Get the voltage deviation △V, then refer to Figure 7 , Figure 7 is the output-input relationship diagram of the voltage adjustment judgment module 323. Figure 7 The input-output relationship shown in the figure is used for voltage regulation, that is, when △V belongs to [-DB, DB], the output is 0, when △V belongs to (-∞, -DB), the output is △V+DB, and when △V belongs to (DB, +∞), the output is △V-DB, where DB is the voltage deviation threshold, and its value is:

[0130]

[0131] Among them, V 1max is the maximum voltage on the primary side of the distribution transformer, a0 is the rated transformation ratio of the distribution transformer, △a is the transformation ratio difference between adjacent taps, and n max is the maximum number of taps.

[0132] In the distribution transformer, the on-off state of the power electronic switch corresponding to each tap needs to be stored. In order to reduce the impact of the tap switching process on the power electronic switch, the sampling and storage module 325 stores the voltage regulation information of the voltage regulation ratio, and the zero-crossing detection module 327 performs zero-crossing detection on the primary side voltage of the transformer. Then, according to the on-off state of the power electronic switch of the distribution transformer and the voltage regulation information, the tap switching is realized at the voltage zero-crossing point.

[0133] Since the transformer tap is discontinuous, and the voltage regulation ratio obtained by the control system is a continuous value, according to the principle of minimum absolute value of the ratio difference, see Figure 4 , a relationship diagram between the voltage regulation ratio and the tap ratio of the distribution transformer, the digital converter module 326 performs digital conversion on the voltage regulation ratio obtained by the control system, and the power electronic on-load voltage regulation distribution transformer 310 performs tap switching according to the tap ratio.

[0134] In one embodiment, a computer device is also provided, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a method for detecting the voltage regulation ratio of a distribution transformer as described in any one of the above embodiments is implemented.

[0135] The computer device, when its processor executes a program, implements any one of the distribution transformer voltage regulation ratio detection methods in the above-mentioned embodiments, thereby being able to adjust the distribution transformer voltage regulation ratio in real time according to the difference between the voltage deviation value and the preset voltage deviation threshold, thereby improving the switching speed and accuracy of the distribution transformer voltage regulation ratio, meeting the requirements of the power electronic switch for rapidity and accuracy, being able to quickly and accurately control the power electronic switch according to the voltage regulation ratio, effectively adjusting the output voltage of the distribution transformer, and providing a basis for the design of a power electronic on-load voltage regulation distribution transformer.

[0136] In addition, those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment method can be implemented by instructing related hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. For example, in the embodiment of the present invention, the program can be stored in a storage medium of a computer system and executed by at least one processor in the computer system to implement the process of the embodiment of the detection method of the voltage regulation ratio of each distribution transformer as described above.

[0137] In one embodiment, a storage medium is further provided, on which a computer program is stored, wherein when the program is executed by a processor, the method for detecting the voltage regulation ratio of a distribution transformer in any of the above embodiments is implemented. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM).

[0138] The computer storage medium and the computer program stored therein can adjust the voltage regulation ratio of the distribution transformer in real time according to the difference between the voltage deviation value and the preset voltage deviation threshold value by implementing the process of the embodiments including the detection method of the voltage regulation ratio of the distribution transformer as mentioned above, thereby improving the switching speed and accuracy of the voltage regulation ratio of the distribution transformer, meeting the requirements of the power electronic switch for rapidity and accuracy, being able to quickly and accurately control the power electronic switch according to the voltage regulation ratio, effectively adjusting the output voltage of the distribution transformer, and providing a basis for the design of the power electronic on-load voltage regulation distribution transformer.

[0139] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0140] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for detecting the voltage regulation ratio of a distribution transformer, characterized in that: The following steps are involved: Calculate the initial distribution transformer voltage regulation ratio according to the primary side input voltage amplitude, secondary side current amplitude and secondary side current phase value of the distribution transformer; Obtaining the fundamental component and harmonic component of the secondary side output voltage; calculating the instantaneous effective value of the secondary side output voltage of the distribution transformer using a numerical matrix according to the fundamental component and harmonic component of the secondary side output voltage; obtaining the voltage deviation value according to the voltage standard value and the instantaneous effective value of the secondary side output voltage of the distribution transformer; If the voltage deviation value is within the preset voltage deviation threshold, the current actual transformation ratio of the distribution transformer is used as the voltage regulation transformation ratio of the distribution transformer; if the voltage deviation value exceeds the preset voltage deviation threshold, the difference between the voltage deviation value and the preset voltage deviation threshold is obtained; The preset voltage deviation threshold is determined by: obtaining the rated transformation ratio of the distribution transformer, the difference in the transformation ratio of adjacent taps, the maximum amplitude of the primary side voltage of the distribution transformer, and the maximum number of taps; and calculating the preset voltage deviation threshold according to the following formula using the rated transformation ratio of the distribution transformer, the difference in the transformation ratio of adjacent taps, the maximum amplitude of the primary side voltage of the distribution transformer, and the maximum number of taps: Among them, V 1max is the maximum voltage amplitude of the primary side of the distribution transformer, a0 is the rated transformation ratio of the distribution transformer, Δa is the transformation ratio difference between adjacent taps, and n max is the maximum number of taps; The difference is integrated to obtain an integral value, and the initial distribution transformer voltage regulation ratio is compensated according to the integral value to obtain the distribution transformer voltage regulation ratio.

2. The method for detecting the voltage regulation ratio of a distribution transformer according to claim 1, characterized in that: The step of calculating the initial distribution transformer voltage regulation ratio according to the primary side input voltage amplitude, the secondary side current amplitude and the secondary side current phase value of the distribution transformer comprises the following steps: Establishing a distribution transformer model according to the primary and secondary side circuit structure of the distribution transformer, and obtaining a distribution transformer voltage regulation ratio calculation model according to the distribution transformer model; The initial distribution transformer voltage regulation ratio is calculated according to the distribution transformer voltage regulation ratio calculation model using the primary side input voltage amplitude, secondary side current amplitude and secondary side current phase value of the distribution transformer.

3. The method for detecting the voltage regulation ratio of a distribution transformer according to claim 2, characterized in that: The calculation model of the voltage regulation ratio of the distribution transformer is as follows: Among them, V ref is the voltage standard value, V1 is the primary input voltage amplitude of the distribution transformer, I2 and θ I are the secondary current amplitude and phase of the distribution transformer, Z and θ Z are the magnitude and phase of the total circuit impedance, respectively.

4. A detection system for the voltage regulation ratio of a distribution transformer, characterized in that: include: A voltage regulation ratio acquisition module is used to calculate the initial distribution transformer voltage regulation ratio according to the primary side input voltage amplitude, secondary side current amplitude and secondary side current phase value of the distribution transformer; A voltage deviation value acquisition module is used to acquire the fundamental component and harmonic component of the secondary side output voltage; calculate the instantaneous effective value of the secondary side output voltage of the distribution transformer using a numerical matrix according to the fundamental component and harmonic component of the secondary side output voltage; and acquire the voltage deviation value according to the voltage standard value and the instantaneous effective value of the secondary side output voltage of the distribution transformer; A voltage regulation judgment module is used to determine that if the voltage deviation value is within a preset voltage deviation threshold, the current actual transformation ratio of the distribution transformer is used as the voltage regulation transformation ratio of the distribution transformer; if the voltage deviation value exceeds the preset voltage deviation threshold, the difference between the voltage deviation value and the preset voltage deviation threshold is obtained; The preset voltage deviation threshold is determined by: obtaining the rated transformation ratio of the distribution transformer, the difference in the transformation ratio of adjacent taps, the maximum amplitude of the primary side voltage of the distribution transformer, and the maximum number of taps; and calculating the preset voltage deviation threshold according to the following formula using the rated transformation ratio of the distribution transformer, the difference in the transformation ratio of adjacent taps, the maximum amplitude of the primary side voltage of the distribution transformer, and the maximum number of taps: Among them, V 1max is the maximum voltage amplitude of the primary side of the distribution transformer, a0 is the rated transformation ratio of the distribution transformer, Δa is the transformation ratio difference between adjacent taps, and n max is the maximum number of taps; The voltage regulation ratio compensation module is used to integrate the difference to obtain an integral value, and compensate the initial distribution transformer voltage regulation ratio according to the integral value to obtain the distribution transformer voltage regulation ratio.

5. A control method for a distribution transformer, characterized in that: The following steps are involved: Detecting the voltage regulation ratio of a distribution transformer using the method for detecting the voltage regulation ratio of a distribution transformer as described in any one of claims 1 to 3; The on-off of the power electronic switch in the distribution transformer is controlled according to the voltage regulation ratio of the distribution transformer to switch the tap.

6. The control method of the distribution transformer according to claim 5, characterized in that: The step of controlling the on and off of the power electronic switch in the distribution transformer according to the transformation ratio of the distribution transformer and switching the tap comprises the following steps: If the primary side voltage amplitude reaches zero, digitally convert the voltage regulation ratio of the distribution transformer to obtain the tap ratio of the distribution transformer; The on and off of the power electronic switch in the distribution transformer is controlled according to the tap ratio to switch the tap.

7. A voltage regulating distribution transformer, characterized in that: It comprises a power electronic on-load voltage-regulating distribution transformer and a distribution transformer voltage-regulating ratio controller, wherein the distribution transformer voltage-regulating ratio controls the power electronic on-load voltage-regulating distribution transformer switching tap using the distribution transformer control method according to claim 5 or 6.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 5 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 5 to 6 are implemented.

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