Online synchronous vector monitoring device and method for electrical parameter complex field of distribution transformer

Abstract

The embodiment of the invention discloses a distribution transformer electrical parameter complex field on-line synchronous vector monitoring device and method, and the device comprises a high-precision synchronous vector measurement and collection module and a controller, and the high-precision synchronous vector measurement and collection module is connected with the controller. The high-precision synchronous vector measurement and acquisition module is used for being connected with a neutral line at the low-voltage side of the distribution transformer to be measured and a three-phase line at an outlet, and is used for measuring and synchronously acquiring a zero-sequence voltage vector and a neutral line current vector at the low-voltage side of the distribution transformer to be measured. The controller is used for determining the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral current vector, so as to determine the load loss and the short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance, namely, the zero-sequence voltage vector and the neutral current vector are simply and synchronously measured on the low-voltage side of the distribution transformer. Therefore, on-line monitoring of short-circuit complex impedance and electrical parameters can be realized, and problems in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer parameter monitoring, and particularly to an on-line synchronous vector monitoring device and method for electrical parameters of a distribution transformer in the complex number domain. Background Art

[0002] Electrical parameters such as load loss and short-circuit voltage (also known as impedance voltage) of a distribution transformer are extremely important parameters, which represent the operation efficiency and performance of the distribution transformer. On the one hand, when the electrical parameters such as load loss and short-circuit voltage of the distribution transformer are too high, the energy conversion efficiency of the distribution transformer is low, resulting in energy waste; on the other hand, when the distribution transformer operates for a long time, it will inevitably be affected by the environment, external faults, etc., resulting in parameter changes, and even major defects, reducing the reliability. It can be seen that the load loss and short-circuit voltage of the distribution transformer reflect the performance and health status of the distribution transformer. Therefore, it is necessary to detect the electrical parameters such as load loss and short-circuit voltage of the distribution transformer during the network access and routine preventive tests of the distribution transformer.

[0003] Currently, the electrical parameters such as load loss and short-circuit voltage of the distribution transformer are mainly obtained through off-line tests. For a distribution transformer that has been put into operation, it is necessary to withdraw the distribution transformer from operation to conduct relevant tests, which is time-consuming, laborious and requires power outage, affecting the power supply continuity.

[0004] Therefore, professionals have studied the on-line detection method for electrical parameters of the distribution transformer, and monitored whether the electrical parameters such as load loss and short-circuit voltage of the distribution transformer have changed significantly by real-time detecting the short-circuit impedance of the distribution transformer, so as to judge whether the health status of the distribution transformer meets the operation requirements and prevent major faults of the distribution transformer.

[0005] The literature "Research on On-line Detection Method for Loss and Capacity of Distribution Transformer (Wu Xihong)" proposes to calculate the short-circuit loss and no-load loss of the distribution transformer by on-line detecting the voltage and current on both sides of the distribution transformer. However, on the one hand, in the implementation process of this method, when measuring the high-voltage side voltage and current, it is necessary to add high-voltage voltage and current sensing devices (such as PT, CT), and the cost of the high-voltage sensing device is equivalent to the cost of the distribution transformer, and the implementation cost is relatively high; on the other hand, this method requires that the high-voltage side voltage of the distribution transformer is basically unchanged, but due to the inevitable voltage fluctuation on the high-voltage side in actual operation, the measurement error is relatively large; furthermore, this method is also easily affected by harmonics and three-phase imbalance, further increasing the measurement error.

[0006] In the literature "Online Detection Method of Short - Circuit Reactance of Distribution Transformers Considering Asymmetric Loads (Chen Minyou)" and "An Improved Online Detection Method of Short - Circuit Reactance of Distribution Transformers (Wang Minglin)", it is proposed to collect the three - phase voltages on the high - voltage side, the three - phase currents on the high - voltage side, the three - phase voltages on the low - voltage side, the three - phase currents on the low - voltage side, and the neutral - point voltage offset on the high - voltage side of the distribution transformer multiple times under different loads, and calculate the short - circuit reactance of the distribution transformer. On the one hand, this method requires installing high - voltage voltage and current sensing devices on the high - voltage side of the distribution transformer, and the implementation cost is relatively high; on the other hand, this method depends on load changes, has poor real - time performance, and can only obtain the short - circuit reactance.

[0007] The patent "Online Monitoring Method and System for Transformer Resistance Parameters Based on Winding Temperature Changes (CN119246953A)" discloses calculating the winding resistance (i.e., the short - circuit resistance in the short - circuit impedance) through an oil - temperature sensor and a simulation model. However, this method is an indirect measurement, relying on the accuracy of simulation results, the effectiveness of fitting curves, and material limitations, etc., and the implementation difficulty is relatively large, and the accuracy is difficult to guarantee. And this method can only calculate the short - circuit resistance in the short - circuit impedance of the distribution transformer, and cannot monitor the short - circuit reactance parameter in the short - circuit impedance.

[0008] The patent "A Calculation Method for Zero - Sequence Impedance of Distribution Transformers (CN108075469B)" discloses constructing a zero - sequence impedance complex equation and using a genetic algorithm to solve and calculate the zero - sequence impedance. The purpose of this method is to calculate the zero - sequence impedance. Although the zero - sequence impedance complex equation contains the short - circuit impedance, the short - circuit impedance of this method uses the factory parameters, and the short - circuit impedance cannot be calculated and online monitored using the zero - sequence impedance complex equation.

[0009] It can be seen that the real - time monitoring of the electrical parameters of distribution transformers is crucial for ensuring the safe operation of the power grid. However, traditional methods rely on power - off tests or accessing equipment on the high - voltage side, and there are problems such as potential safety hazards and low efficiency. Although the existing online monitoring technologies have been improved to some extent, there are still problems such as high implementation cost, high difficulty, large measurement errors, and inability to monitor short - circuit complex impedance. Summary of the Invention

[0010] Based on this, in view of the above problems, it is necessary to propose an online synchronous vector monitoring device and method for the electrical parameters of distribution transformers in the complex number domain. By simply synchronously measuring the zero - sequence voltage vector and the neutral - line current vector on the low - voltage side of the distribution transformer, the online monitoring of short - circuit complex impedance and electrical parameters can be realized to solve the problems existing in the prior art.

[0011] To achieve the above object, in the first aspect of the present invention, an online synchronous vector monitoring device for the electrical parameters of a distribution transformer in the complex number domain is provided. The device includes a high - precision synchronous vector measurement and acquisition module and a controller;

[0012] The high-precision synchronous vector measurement acquisition module is connected to the controller;

[0013] The high-precision synchronous vector measurement acquisition module is used to be respectively connected to the neutral line of the low-voltage side of the distribution transformer to be measured and the three-phase phase lines at the outlet, and is used to measure and synchronously acquire the zero-sequence voltage vector and the neutral line current vector of the low-voltage side of the distribution transformer to be measured;

[0014] The controller is used to determine the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector, so as to determine the load loss and the short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance.

[0015] Optionally, the controller is further used to determine the complex impedance of the high-voltage side to the low-voltage side of the distribution transformer to be measured according to the rated voltage ratio of the high-voltage side to the low-voltage side of the distribution transformer to be measured, the zero-sequence voltage vector and the neutral line current vector, and use the complex impedance as the short-circuit complex impedance.

[0016] Optionally, the high-precision synchronous vector measurement acquisition module includes a voltage transformation module, a current sensing module and a synchronous vector precise acquisition module;

[0017] The voltage transformation module and the current sensing module are both connected to the synchronous vector precise acquisition module, and the synchronous vector precise acquisition module is connected to the controller;

[0018] The voltage transformation module is used to be respectively connected to the neutral line of the low-voltage side of the distribution transformer to be measured and the three-phase phase lines at the outlet, and the current sensing module is used to be connected to the neutral line of the low-voltage side of the distribution transformer to be measured;

[0019] The voltage transformation module is used to measure the zero-sequence voltage vector;

[0020] The current sensing module is used to measure the neutral line current vector;

[0021] The synchronous vector precise acquisition module is used to synchronously acquire the zero-sequence voltage vector and the neutral line current vector.

[0022] Optionally, the voltage transformation module includes a first impedance, a second impedance and a third impedance;

[0023] One end of the first impedance and one end of the second impedance are both connected to one end of the third impedance to form a first impedance access end;

[0024] The other ends of the first impedance, the second impedance, and the third impedance are respectively used to connect to the three-phase phase lines at the low-voltage side outlet of the distribution transformer to be measured, and the first impedance access end is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured.

[0025] Optionally, the device further includes an imbalance adjustment module;

[0026] The imbalance adjustment module is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured and the three-phase phase lines at the outlet respectively;

[0027] When the voltage amplitude of the zero-sequence voltage vector is less than the start threshold, the imbalance adjustment module is used to adjust the three-phase imbalance degree of the low-voltage side of the distribution transformer to be measured until the voltage amplitude of the zero-sequence voltage vector is greater than or equal to the start threshold.

[0028] Optionally, the imbalance adjustment module includes a first unbalanced impedance, a second unbalanced impedance, a third unbalanced impedance, and a first switching switch;

[0029] One end of the first unbalanced impedance and one end of the second unbalanced impedance are both connected to one end of the third unbalanced impedance to form a first unbalanced access end, and the first unbalanced access end is connected to one end of the first switching switch;

[0030] The other ends of the first unbalanced impedance, the second unbalanced impedance, and the third unbalanced impedance are respectively used to connect to the three-phase phase lines at the low-voltage side outlet of the distribution transformer to be measured, and the other end of the first switching switch is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured;

[0031] Among them, at least one of the first unbalanced impedance, the second unbalanced impedance, and the third unbalanced impedance is an adjustable unbalanced impedance.

[0032] Optionally, the imbalance adjustment module includes a fourth unbalanced impedance, a second switching switch, a third switching switch, and a fourth switching switch;

[0033] One end of the second switching switch and one end of the third switching switch are both connected to one end of the fourth switching switch to form a second unbalanced end, and the second unbalanced end is connected to one end of the fourth unbalanced impedance;

[0034] The other ends of the second switching switch, the third switching switch, and the fourth switching switch are respectively used to connect to the three-phase phase lines at the low-voltage side outlet of the distribution transformer to be measured, and the other end of the fourth unbalanced impedance is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured.

[0035] To achieve the above object, in a second aspect, the present invention provides a method for online synchronous vector monitoring of electrical parameters of a distribution transformer in the complex number domain. The method includes:

[0036] Obtain the zero-sequence voltage vector and the neutral line current vector on the low-voltage side of the distribution transformer to be measured;

[0037] Determine the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector;

[0038] Determine the load loss and short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance.

[0039] Optionally, the determining the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector includes:

[0040] Obtain the rated voltage ratio of the high-voltage side to the low-voltage side of the distribution transformer to be measured;

[0041] Determine the complex impedance of the high-voltage side to the low-voltage side of the distribution transformer to be measured according to the rated voltage ratio, the zero-sequence voltage vector, and the neutral line current vector;

[0042] Use the complex impedance as the short-circuit complex impedance.

[0043] Optionally, the determining the neutral line of the high-voltage side to the low-voltage side of the distribution transformer to be measured according to the rated voltage ratio, the zero-sequence voltage vector, and the neutral line current vector includes:

[0044] Use the formula to determine the complex impedance;

[0045] where Z 12 is the complex impedance, is the zero-sequence voltage vector, is the neutral line current vector, and k is the rated voltage ratio.

[0046] To achieve the above object, in a third aspect, the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a controller, the controller is caused to execute the method according to any one of the first aspects.

[0047] To achieve the above object, in a fourth aspect, the present invention provides a computer device including a memory and a controller. The memory stores a computer program. When the computer program is executed by the controller, the controller is caused to execute the method according to any one of the first aspects.

[0048] Adopting the embodiment of the present invention has the following beneficial effects: The above device includes a high-precision synchronous vector measurement acquisition module and a controller; the high-precision synchronous vector measurement acquisition module is connected to the controller; the high-precision synchronous vector measurement acquisition module is used to be respectively connected to the neutral line of the low-voltage side of the distribution transformer to be measured and the three-phase phase lines at the outlet, and is used to measure and synchronously acquire the zero-sequence voltage vector and the neutral line current vector of the low-voltage side of the distribution transformer to be measured; the controller is used to determine the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector, so as to determine the load loss and short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance. That is, this method does not require high-voltage sensing equipment to be connected to the high-voltage side, reducing the implementation cost, and at the same time avoiding the safety hazards brought by high-voltage side operations. Moreover, since the zero-sequence voltage and the neutral line current of the low-voltage side are measured and synchronously acquired, it is less affected by factors such as voltage fluctuations, harmonics, and three-phase imbalance, improving the measurement accuracy. And as long as the zero-sequence voltage vector and the neutral line current vector are simply synchronously measured, online monitoring can be realized, greatly reducing the implementation difficulty and improving the efficiency of the online monitoring technology. Moreover, this method realizes the real-time online monitoring of the electrical parameters of the distribution transformer, can detect the load loss and short-circuit voltage of the distribution transformer under the operating state of the distribution transformer, so as to detect the change of the electrical parameters of the distribution transformer as early as possible, prevent the long-term accumulation of minor faults of the distribution transformer from not being solved, and prevent the entire power system from being affected by major faults of the distribution transformer, which has an important role in discovering early faults of the distribution transformer and ensuring the safe and stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] 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 also be obtained based on these drawings.

[0050] Wherein:

[0051] Figure 1 is a schematic diagram of the online synchronous vector monitoring device for the electrical parameters of the distribution transformer in the embodiment of the present application Figure 1 ;

[0052] Figure 2 is a schematic diagram of the online synchronous vector monitoring device for the electrical parameters of the distribution transformer in the embodiment of the present application Figure 2 ;

[0053] Figure 3 is a schematic diagram of the online synchronous vector monitoring device for the electrical parameters of the distribution transformer in the embodiment of the present application Figure 3 ;

[0054] Figure 4 Schematic diagram of the on-line synchronous vector monitoring device for the electrical parameters of the distribution transformer in the embodiment of the present application Figure 4 ;

[0055] Figure 5 Schematic diagram of the on-line synchronous vector monitoring device for the electrical parameters of the distribution transformer in the embodiment of the present application Figure 5 ;

[0056] Figure 6 Schematic diagram of the on-line synchronous vector monitoring device for the electrical parameters of the distribution transformer in the embodiment of the present application Figure 6 ;

[0057] Figure 7 Schematic diagram of the on-line synchronous vector monitoring method for the electrical parameters of the distribution transformer in the embodiment of the present application;

[0058] Figure 8 Schematic diagram of the equivalent detection circuit on the low-voltage side of the distribution transformer to be measured in the embodiment of the present application;

[0059] Figure 9 Internal structure diagram of a computer device in some embodiments. Detailed implementation manners

[0060] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0061] Electrical parameters such as the load loss and short-circuit voltage (also known as impedance voltage) of the distribution transformer are extremely important parameters, representing the operation efficiency and performance of the distribution transformer. On the one hand, when the electrical parameters such as the load loss and short-circuit voltage of the distribution transformer are too high, the energy conversion efficiency of the distribution transformer is low, resulting in energy waste; on the other hand, during the long-term operation of the distribution transformer, it is inevitably affected by the environment, external faults, etc., resulting in parameter changes, and even major defects, reducing the reliability. It can be seen that the load loss and short-circuit voltage of the distribution transformer reflect the performance and health status of the distribution transformer. Therefore, it is necessary to detect the electrical parameters such as the load loss and short-circuit voltage of the distribution transformer during the network access and regular preventive tests of the distribution transformer.

[0062] Currently, the electrical parameters such as the load loss and short-circuit voltage of the distribution transformer are mainly obtained through off-line tests. For the distribution transformers that have been put into operation, the relevant tests need to be carried out after the distribution transformers are taken out of operation, which is time-consuming, laborious and requires power outage, affecting the power supply continuity.

[0063] Therefore, professionals have studied the on-line detection method of the electrical parameters of distribution transformers. By real-time detecting the short-circuit impedance of the distribution transformer, it is monitored whether there are obvious changes in the electrical parameters such as the load loss and short-circuit voltage of the distribution transformer, so as to judge whether the health status of the distribution transformer meets the operation requirements and prevent major faults of the distribution transformer from occurring.

[0064] In the literature "Research on the On-line Detection Method of Distribution Transformer Loss and Capacity (Wu Xihong)", it is proposed to calculate the short-circuit loss and no-load loss of the distribution transformer by on-line detecting the voltage and current on both sides of the distribution transformer. However, on the one hand, in the implementation process of this method, high-voltage voltage and current sensing devices (such as PT, CT) need to be added to measure the high-voltage side voltage and current. The cost of the high-voltage sensing device is equivalent to that of the distribution transformer, and the implementation cost is relatively high. On the other hand, this method requires that the high-voltage side voltage of the distribution transformer is basically unchanged. However, due to the inevitable voltage fluctuation on the high-voltage side in actual operation, the measurement error is relatively large. Moreover, this method is also easily affected by harmonics and three-phase unbalance, further increasing the measurement error.

[0065] In the literature "On-line Detection Method of Short-circuit Reactance of Distribution Transformer Considering Asymmetric Load (Chen Minyou)" and "An Improved On-line Detection Method of Short-circuit Reactance of Distribution Transformer (Wang Minglin)", it is proposed to collect the three-phase voltage on the high-voltage side, the three-phase current on the high-voltage side, the three-phase voltage on the low-voltage side, the three-phase current on the low-voltage side and the neutral point voltage offset on the high-voltage side of the distribution transformer multiple times under different loads, and calculate the short-circuit reactance of the distribution transformer. On the one hand, this method requires high-voltage voltage and current sensing devices to be installed on the high-voltage side of the distribution transformer, and the implementation cost is relatively high. On the other hand, this method depends on the load change, and the real-time performance is poor and only the short-circuit reactance can be obtained.

[0066] The patent "On-line Monitoring Method and System for Transformer Resistance Parameters Based on Winding Temperature Change (CN119246953A)" discloses calculating the winding resistance (i.e., the short-circuit resistance in the short-circuit impedance) through an oil temperature sensor and a simulation model. However, this method is an indirect measurement, which depends on the accuracy of the simulation results, the effectiveness of the fitting curve and material limitations, etc. The implementation difficulty is relatively large and the accuracy is difficult to guarantee. And this method can only calculate the short-circuit resistance in the short-circuit impedance of the distribution transformer, and cannot monitor the short-circuit reactance parameter in the short-circuit impedance.

[0067] The patent "A Calculation Method for Zero-sequence Impedance of Distribution Transformer (CN108075469B)" discloses calculating the zero-sequence impedance by constructing a zero-sequence impedance complex equation and using a genetic algorithm for solution. The purpose of this method is to calculate the zero-sequence impedance. Although the zero-sequence impedance complex equation contains the short-circuit impedance, the short-circuit impedance of this method uses the factory parameters, and the short-circuit impedance cannot be calculated and on-line monitored by using the zero-sequence impedance complex equation.

[0068] It can be seen that the real-time monitoring of the electrical parameters of distribution transformers is crucial for ensuring the safe operation of the power grid. However, traditional methods rely on power outage tests or equipment connected to the high-voltage side, which have problems such as safety hazards and low efficiency. Although existing online monitoring technologies have been improved to some extent, there are still problems such as high implementation costs, high difficulties, large measurement errors, and the inability to monitor short-circuit complex impedance.

[0069] To address the above problems, this application proposes an online synchronous vector monitoring device and method for the electrical parameters of distribution transformers in the complex number domain. By simply synchronously measuring the zero-sequence voltage vector and the neutral line current vector on the low-voltage side of the distribution transformer, online monitoring of short-circuit complex impedance and electrical parameters can be achieved, so as to solve the problems existing in the prior art. The specific implementation principle will be described in detail in the following embodiments.

[0070] This application provides an online synchronous vector monitoring device for the electrical parameters of distribution transformers in the first aspect.

[0071] Please refer to Figure 1 for the schematic diagram of the online synchronous vector monitoring device for the electrical parameters of distribution transformers in the embodiments of this application. Figure 1 This device includes a high-precision synchronous vector measurement and acquisition module 110 and a controller 120.

[0072] Among them, the high-precision synchronous vector measurement and acquisition module 110 is connected to the controller 120.

[0073] In a feasible implementation manner, the high-precision synchronous vector measurement and acquisition module 110 is used to be respectively connected to the neutral line and the three-phase phase lines at the outlet on the low-voltage side of the distribution transformer to be measured, and is used to measure and synchronously acquire the zero-sequence voltage vector and the neutral line current vector on the low-voltage side of the distribution transformer to be measured; the controller 120 is used to determine the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector, so as to determine the load loss and short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance.

[0074] Among them, the distribution transformer to be measured refers to the distribution transformer that needs to be monitored online.

[0075] It should be particularly noted that this application only needs to simply synchronously measure two variables, namely the zero-sequence voltage vector and the neutral line current vector, on the low-voltage side of the distribution transformer to achieve online monitoring, without the need to measure other variables.

[0076] For the determination method of the load loss and short-circuit voltage of the distribution transformer to be measured, in some embodiments, the load loss and impedance voltage of the distribution transformer to be measured can be determined according to the rated capacity of the distribution transformer to be measured, the rated voltage on the high-voltage side of the distribution transformer to be measured, and the short-circuit complex impedance.

[0077] Specifically, the formula can be used to determine the load loss and short-circuit voltage of the distribution transformer to be measured; where P S is the load loss of the distribution transformer to be measured, with the unit of kW, real() is the real part extraction function, Z is the short-circuit complex impedance, S N is the rated capacity of the distribution transformer to be measured, U N is the rated voltage on the high-voltage side of the distribution transformer to be measured, U X % is the short-circuit voltage of the distribution transformer to be measured, and imag() is the imaginary part extraction function.

[0078] Of course, in some other embodiments, some other existing calculation methods for determining the load loss and short-circuit voltage of the distribution transformer to be measured based on the short-circuit complex impedance can also be adopted.

[0079] After obtaining the load loss and short-circuit voltage of the distribution transformer to be measured, in some embodiments, the controller 120 is further configured to determine whether the distribution transformer to be measured has a fault according to the first comparison result between the load loss of the distribution transformer to be measured and the load loss on the factory nameplate, and the second comparison result between the short-circuit voltage of the distribution transformer to be measured and the short-circuit voltage on the factory nameplate.

[0080] In the embodiments of the present application, this method does not require a high-voltage sensing device to be connected to the high-voltage side, reducing the implementation cost. At the same time, it avoids the safety hazards brought by high-voltage side operations. Moreover, since the zero-sequence voltage and neutral line current on the low-voltage side are measured and synchronously collected, it is less affected by factors such as voltage fluctuations, harmonics, and three-phase unbalances, improving the measurement accuracy. And as long as two variables, namely the zero-sequence voltage vector and the neutral line current vector, are simply measured, the on-line monitoring of the short-circuit complex impedance can be realized, greatly reducing the implementation difficulty and improving the efficiency of the on-line monitoring technology. Moreover, this method realizes the real-time on-line monitoring of the complex number domain of the electrical parameters of the distribution transformer, can detect the load loss and short-circuit voltage of the distribution transformer under the operating state of the distribution transformer, so as to discover the change of the electrical parameters of the distribution transformer as early as possible, prevent the long-term accumulation of minor faults of the distribution transformer from not being solved, and prevent the entire power system from being affected by major faults of the distribution transformer, which plays an important role in discovering early faults of the distribution transformer and ensuring the safe and stable operation of the power system.

[0081] In a feasible implementation manner, the controller 120 in the above embodiments is further configured to determine the complex impedance from the high-voltage side to the low-voltage side of the distribution transformer to be measured according to the rated voltage ratio from the high-voltage side to the low-voltage side, the zero-sequence voltage vector, and the neutral line current vector of the distribution transformer to be measured, and use the complex impedance as the short-circuit complex impedance.

[0082] It should be noted that since the low-voltage side measurement and acquisition are adopted in this application, and the short-circuit complex impedance refers to the short-circuit complex impedance from the high-voltage side to the low-voltage side, it is necessary to introduce the rated voltage ratio from the high-voltage side to the low-voltage side to determine the complex impedance from the high-voltage side to the low-voltage side, and then use the complex impedance as the short-circuit complex impedance.

[0083] In some embodiments, the controller 120 is further configured to use the formula to determine the complex impedance; where Z 12 is the complex impedance, is the zero-sequence voltage vector, is the neutral line current vector, and k is the rated voltage ratio.

[0084] In the embodiments of the present application, by determining the complex impedance according to the rated voltage ratio from the high-voltage side to the low-voltage side, the zero-sequence voltage vector, and the neutral line current vector of the distribution transformer to be measured, and using the complex impedance as the short-circuit complex impedance, not only the measurement accuracy is improved, but also the measurement process is simplified, the adaptability of the system is enhanced, and a basis is provided for subsequent analysis, which is of great significance for the online monitoring and fault prevention of distribution transformers.

[0085] It can be understood that the measurement accuracy is improved: by introducing the rated voltage ratio from the high-voltage side to the low-voltage side and combining the zero-sequence voltage vector and the neutral line current vector measured on the low-voltage side, the complex impedance from the high-voltage side to the low-voltage side can be calculated more accurately. This calculation method takes into account the rated voltage ratio on both sides of the distribution transformer, making the measurement result more in line with the actual operation situation and improving the measurement accuracy; the measurement process is simplified: the traditional online monitoring method may require high-voltage sensing equipment to be connected on the high-voltage side, which not only increases the implementation cost but also brings potential safety hazards. In this application, only simple measurements need to be carried out on the low-voltage side to obtain the complex impedance from the high-voltage side to the low-voltage side, greatly simplifying the measurement process.

[0086] Based on Figure 1 , please refer to Figure 2 , which is a schematic diagram of the online synchronous vector monitoring device for the electrical parameters of the distribution transformer in the embodiments of the present application Figure 2 In the above-mentioned embodiments, the high-precision synchronous vector measurement and acquisition module 110 includes a voltage conversion module 111, a current sensing module 112, and a synchronous vector precise acquisition module 113.

[0087] Among them, the voltage conversion module 111 and the current sensing module 112 are both connected to the synchronous vector precise acquisition module 113, and the synchronous vector precise acquisition module 113 is connected to the controller 120.

[0088] In a feasible implementation, the voltage conversion module 111 is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured and the three-phase phase lines at the outlet respectively, and the current sensing module 112 is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured; the voltage conversion module 111 is used to measure the zero-sequence voltage vector; the current sensing module 112 is used to measure the neutral line current vector; the synchronous vector precise acquisition module 113 is used to synchronously acquire the zero-sequence voltage vector and the neutral line current vector.

[0089] Wherein, Figure 2 shown is the zero-sequence voltage vector, is the neutral line current vector, A, B, and C are the three-phase phase lines at the outlet of the low-voltage side of the distribution transformer to be measured, and N is the neutral line of the low-voltage side of the distribution transformer to be measured.

[0090] In the embodiment of the present application, by adopting the high-precision synchronous vector measurement and acquisition module 110 composed of the voltage conversion module 111, the current sensing module 112, and the synchronous vector precise acquisition module 113, not only the accuracy and reliability of the measurement are improved, but also the measurement connection and wiring are simplified, the adaptability and expandability of the system are enhanced, and the synchronism and real-time performance of data acquisition are improved, providing strong support for the online monitoring and fault prevention of the distribution transformer.

[0091] It can be understood that the accuracy and reliability of the measurement are improved: the voltage conversion module 111 and the current sensing module 112 are respectively responsible for measuring the zero-sequence voltage vector and the neutral line current vector. This clear division of labor in measurement helps to improve the accuracy and reliability of the measurement. At the same time, the synchronous vector precise acquisition module 113 ensures the synchronous acquisition of the two variables, avoiding measurement errors caused by time differences; the measurement connection and wiring are simplified: the voltage conversion module 111 is connected to the neutral line and the three-phase phase lines of the low-voltage side of the distribution transformer to be measured, and the current sensing module 112 is connected to the neutral line of the low-voltage side. This connection method is simple and clear, reducing the complexity of wiring and the possibility of errors; the synchronism and real-time performance of data acquisition are improved: the synchronous vector precise acquisition module 113 can ensure the synchronous acquisition of the zero-sequence voltage vector and the neutral line current vector, which is crucial for subsequent data processing and analysis. The synchronously acquired data can more accurately reflect the actual operating state of the distribution transformer, providing a reliable basis for fault prevention and condition assessment.

[0092] Based on Figure 2 , please refer to Figure 3 , which is a schematic diagram of the on-line synchronous vector monitoring device for the electrical parameters of the distribution transformer in the embodiment of the present application Figure 3 The voltage conversion module 111 in the above embodiment includes a first impedance, a second impedance, and a third impedance (not labeled in the figure).

[0093] One end of the first impedance and one end of the second impedance are both connected to one end of the third impedance to form a first impedance access terminal.

[0094] In a feasible implementation, the other ends of the first impedance, the second impedance, and the third impedance are respectively used to connect to the three-phase phase lines at the low-voltage side outlet of the distribution transformer to be measured, and the first impedance access terminal is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured.

[0095] In some embodiments, the impedance elements in the first impedance, the second impedance, and the third impedance can adopt at least one of a resistor, an inductor, and a capacitor, or any combination of at least two of them.

[0096] In the embodiments of the present application, by adopting the voltage conversion module 111 composed of the first impedance, the second impedance, and the third impedance, not only is the voltage conversion module 111 simplified, the flexibility and accuracy of measurement are improved, but also the safety of the system is enhanced, and it is convenient for integration and expansion, providing a more reliable and efficient solution for the online monitoring and fault prevention of distribution transformers.

[0097] It can be understood that the voltage conversion module 111 is simplified: by adopting the combination of the first impedance, the second impedance, and the third impedance, a simple voltage conversion module 111 is formed. This structure not only reduces the number of components but also simplifies the wiring, making the implementation of the voltage conversion module 111 easier and more reliable; the flexibility of measurement is improved: the design of the voltage conversion module 111 enables it to be conveniently connected to the three-phase and neutral lines of the low-voltage side of the distribution transformer to be measured. This connection method improves the flexibility of measurement and can adapt to the wiring methods of different distribution transformers without additional modification or adjustment of the distribution transformer; the accuracy of measurement is enhanced: by connecting one end of the first impedance, the second impedance, and the third impedance to form a first impedance access terminal, the zero-sequence voltage vector can be measured more accurately. This measurement method takes into account the balance relationship between the three-phase voltages, helps to reduce measurement errors, and improves the accuracy of measurement; the safety of the system is improved: the voltage conversion module 111 is connected to the low-voltage side of the distribution transformer, avoiding the safety hazards brought by high-voltage side operations. At the same time, since the voltage conversion module 111 uses impedance elements for voltage measurement, these elements usually have high insulation performance and withstand voltage capacity, further improving the safety of the system.

[0098] Based on Figure 1 , please refer to Figure 4 , which is a schematic diagram of the online synchronous vector monitoring device for the electrical parameters of the distribution transformer in the embodiments of the present application Figure 4 This device further includes an imbalance adjustment module 410.

[0099] In a feasible implementation, the unbalance adjustment module 410 is used to connect to the neutral line on the low-voltage side of the distribution transformer to be measured and the three-phase phase lines at the outlet respectively; when the voltage amplitude of the zero-sequence voltage vector is less than the starting threshold, the unbalance adjustment module 410 is used to adjust the three-phase unbalance degree on the low-voltage side of the distribution transformer to be measured until the voltage amplitude of the zero-sequence voltage vector is greater than or equal to the starting threshold.

[0100] Among them, the starting threshold can be set by the operator based on a large amount of experience, experiments or statistics. Of course, it can also be set by the operator according to actual needs.

[0101] It should be noted that since the zero-sequence voltage is a voltage caused by unequal three-phase voltages, if the three-phase unbalance degree is relatively low, it will cause the zero-sequence voltage vector to approach 0, making it impossible to directly measure the zero-sequence voltage vector. Therefore, when performing online monitoring, it is necessary to judge whether the zero-sequence voltage vector meets the starting threshold, and when it does not meet the starting threshold, the three-phase unbalance degree on the low-voltage side of the distribution transformer is adjusted through the unbalance adjustment module 410 so that the zero-sequence voltage vector can be directly measured.

[0102] In some embodiments, preferably, its starting threshold can be twice the minimum resolution voltage of the voltage measurement of the synchronous vector precise acquisition module 113.

[0103] In some embodiments, the unbalance adjustment module 410 is connected to the controller 120. When the voltage amplitude of the zero-sequence voltage vector is less than the starting threshold, the controller 120 is used to adjust the impedance value of the unbalance adjustment module 410 and / or control the three-phase switching switch of the unbalance adjustment module 410 so that the unbalance adjustment module 410 adjusts the three-phase unbalance degree on the low-voltage side of the distribution transformer to be measured until the voltage amplitude of the zero-sequence voltage vector is greater than or equal to the starting threshold.

[0104] In the embodiments of the present application, the design of the unbalance adjustment module 410 not only improves the reliability of measurement and the adaptability of the system, but also simplifies the operation process, prevents measurement errors, and improves the safety of the system, which is of great significance for the online monitoring and fault prevention of distribution transformers.

[0105] It is understandable that the reliability of measurement is improved: by monitoring the voltage amplitude of the zero-sequence voltage vector and automatically adjusting the three-phase unbalance degree when it is less than the starting threshold, it is ensured that the zero-sequence voltage vector can be accurately measured, which avoids the problem that the zero-sequence voltage is too small due to the too small three-phase balance degree and thus cannot be effectively detected, improving the reliability and accuracy of measurement; the adaptability of the system is enhanced: the unbalance adjustment module 410 can automatically adjust the three-phase unbalance degree on the low-voltage side of the distribution transformer according to the actual situation, enabling the system to adapt to different distribution transformers and operating environments, and this self-adaptability enhances the flexibility and practicality of the system; the operation process is simplified: the automatic adjustment reduces the need for manual intervention, and the operator does not need to manually adjust the three-phase unbalance degree of the distribution transformer, thus simplifying the operation process and improving the work efficiency; measurement errors are prevented: by ensuring that the voltage amplitude of the zero-sequence voltage vector is within the measurable range, the unbalance adjustment module 410 helps prevent measurement errors caused by too low voltage, which improves the quality and reliability of the data and provides an accurate basis for subsequent data analysis and fault prevention; the safety of the system is improved: automatically adjusting the three-phase unbalance degree can avoid safety problems that may be caused by improper manual operation. In addition, by maintaining an appropriate zero-sequence voltage level, it helps monitor and timely detect potential faults, thus improving the safety of the entire power system.

[0106] Based on Figure 3 and Figure 4 , please refer to Figure 5 , which is a schematic Figure 5 of the on-line synchronous vector monitoring device for electrical parameters of the distribution transformer in the embodiment of the present application.

[0107] Among them, one end of the first unbalance impedance and one end of the second unbalance impedance are both connected to one end of the third unbalance impedance to form a first unbalance access end, and the first unbalance access end is connected to one end of the first switching switch.

[0108] In a feasible implementation manner, the other ends of the first unbalance impedance, the second unbalance impedance, and the third unbalance impedance are respectively used to connect to the three-phase phase lines at the low-voltage side outlet of the distribution transformer to be measured, and the other end of the first switching switch is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured; among the first unbalance impedance, the second unbalance impedance, and the third unbalance impedance, at least one unbalance impedance is an adjustable unbalance impedance.

[0109] Since at least one of the first unbalanced impedance, the second unbalanced impedance, and the third unbalanced impedance is an adjustable unbalanced impedance, in some embodiments, at least one of the first unbalanced impedance, the second unbalanced impedance, and the third unbalanced impedance is connected to the controller 120. The controller 120 can adjust the impedance value of at least one of the first unbalanced impedance, the second unbalanced impedance, and the third unbalanced impedance to adjust the impedance value of the unbalanced adjustment module 410, so that the unbalanced adjustment module 410 adjusts the three-phase unbalance degree of the low-voltage side of the distribution transformer to be measured.

[0110] In some embodiments, the first switching switch is connected to the controller 120, and the controller 120 can control the closing and opening of the first switching switch.

[0111] In the embodiments of the present application, through its unique design and structure, the unbalanced adjustment module 410, which includes the structure of the first unbalanced impedance, the second unbalanced impedance, the third unbalanced impedance, and the first switching switch, realizes the flexible adjustment of the three-phase unbalance degree of the low-voltage side of the distribution transformer, improves the flexibility, accuracy, safety, and reliability of the on-line synchronous vector monitoring device for the electrical parameters of the distribution transformer in the complex number domain, and provides strong support for the on-line monitoring and fault prevention of the distribution transformer.

[0112] Based on Figure 3 and Figure 4 , please refer to Figure 6 , which is a schematic Figure 6 of the on-line synchronous vector monitoring device for the electrical parameters of the distribution transformer in the embodiments of the present application. The unbalanced adjustment module 410 in the above embodiments includes a fourth unbalanced impedance, a second switching switch, a third switching switch, and a fourth switching switch (not labeled in the figure).

[0113] One end of the second switching switch and one end of the third switching switch are both connected to one end of the fourth switching switch to form a second unbalanced end, and the second unbalanced end is connected to one end of the fourth unbalanced impedance.

[0114] In a feasible implementation manner, the other end of the second switching switch, the other end of the third switching switch, and the other end of the fourth switching switch are respectively used to connect to the three-phase phase lines at the outlet of the low-voltage side of the distribution transformer to be measured, and the other end of the fourth unbalanced impedance is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured.

[0115] It should be noted that the fourth unbalanced impedance can be an adjustable unbalanced impedance or a fixed unbalanced impedance.

[0116] In some embodiments, when the fourth unbalanced impedance is a fixed unbalanced impedance, the second switching switch, the third switching switch, and the fourth switching switch are all connected to the controller 120. The controller 120 can control the closing and opening of the second switching switch, the third switching switch, and the fourth switching switch to control the three-phase switching switch of the unbalance adjustment module 410, so that the unbalance adjustment module 410 adjusts the three-phase unbalance degree of the low-voltage side of the distribution transformer to be measured.

[0117] In other embodiments, when the fourth unbalanced impedance is an adjustable unbalanced impedance, the fourth unbalanced impedance, the second switching switch, the third switching switch, and the fourth switching switch are all connected to the controller 120. The controller 120 can adjust the impedance value of the fourth unbalanced impedance and / or control the closing and opening of the second switching switch, the third switching switch, and the fourth switching switch to adjust the impedance value of the unbalance adjustment module 410 and / or control the three-phase switching switch of the unbalance adjustment module 410, so that the unbalance adjustment module 410 adjusts the three-phase unbalance degree of the low-voltage side of the distribution transformer to be measured.

[0118] In the embodiments of the present application, through its unique another design and structure, the unbalance adjustment module 410, which includes the structure of the fourth unbalanced impedance, the second switching switch, the third switching switch, and the fourth switching switch, realizes the flexible adjustment of the three-phase unbalance degree of the low-voltage side of the distribution transformer, improves the flexibility, accuracy, safety, and reliability of the on-line synchronous vector monitoring device for the electrical parameters of the distribution transformer in the complex number domain, and provides strong support for the on-line monitoring and fault prevention of the distribution transformer.

[0119] The present application provides a method for on-line synchronous vector monitoring of electrical parameters of a distribution transformer in the complex number domain in a second aspect.

[0120] Please refer to Figure 7 , which is a schematic diagram of the method for on-line synchronous vector monitoring of electrical parameters of a distribution transformer in the embodiments of the present application. The method includes:

[0121] Step 710: Obtain the zero-sequence voltage vector and the neutral line current vector of the low-voltage side of the distribution transformer to be measured.

[0122] Step 720: Determine the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector.

[0123] Step 730: Determine the load loss and the short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance.

[0124] For the relevant content of the above steps 710 to 730, reference can be made to the relevant content in the above embodiments, and details will not be repeated here.

[0125] In the embodiment of the present application, by obtaining the zero-sequence voltage vector and the neutral line current vector on the low-voltage side of the distribution transformer to be measured, then determining the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector, and finally determining the load loss and short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance, only two variables, namely the zero-sequence voltage vector and the neutral line current vector, need to be simply measured on the low-voltage side of the distribution transformer to achieve online monitoring, without the need to measure other variables, showing significant advantages in terms of safety, efficiency, cost, accuracy, adaptability, and operation process, providing strong support for the online monitoring and fault prevention of the distribution transformer.

[0126] In a feasible implementation manner, step 720 in the above embodiment, determining the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector, includes: obtaining the rated voltage ratio of the high-voltage side to the low-voltage side of the distribution transformer to be measured; determining the complex impedance of the high-voltage side to the low-voltage side of the distribution transformer to be measured according to the rated voltage ratio, the zero-sequence voltage vector, and the neutral line current vector; and using the complex impedance as the short-circuit complex impedance.

[0127] For the explanation of this embodiment, reference can be made to the relevant content in the above embodiment, and details will not be elaborated here.

[0128] In the embodiment of the present application, by obtaining the rated voltage ratio of the high-voltage side to the low-voltage side of the distribution transformer to be measured, determining the complex impedance of the high-voltage side to the low-voltage side of the distribution transformer to be measured according to the rated voltage ratio, the zero-sequence voltage vector, and the neutral line current vector, and using the complex impedance as the short-circuit complex impedance, not only improves the measurement accuracy, but also simplifies the measurement process, enhances the adaptability of the system, and provides a basis for subsequent analysis, which is of great significance for the online monitoring and fault prevention of the distribution transformer.

[0129] In a feasible implementation manner, determining the complex impedance of the high-voltage side to the low-voltage side of the distribution transformer to be measured according to the rated voltage ratio, the zero-sequence voltage vector, and the neutral line current vector in the above embodiment includes:

[0130] Using the formula to determine the complex impedance;

[0131] where Z 12 is the complex impedance, is the zero-sequence voltage vector, is the neutral line current vector, and k is the rated voltage ratio.

[0132] In the present application, both the complex impedance and the short-circuit complex impedance include resistance and reactance.

[0133] It should be noted that based on the above Figures 1 to 6, this application can pre - construct an equivalent detection circuit for the low - voltage side of the distribution transformer to be measured, and obtain the formula in this embodiment based on the equivalent detection circuit.

[0134] Please refer to Figure 8 , which is a schematic diagram of the equivalent detection circuit for the low - voltage side of the distribution transformer to be measured in the embodiment of this application. The Z shown in this schematic diagram a , Z b , Z c are the impedances from the low - voltage sides of phases A, B, and C of the distribution transformer to be measured to the high - voltage side respectively. is the zero - sequence voltage vector. is the neutral - line current vector, and N is the neutral line of the low - voltage side of the distribution transformer to be measured.

[0135] Since and for the distribution transformer to be measured, the short - circuit impedances of the three - phase windings are generally approximately equal. Therefore, it can be set that Z a ≈Z b ≈Z c =Z 21 , and based on the equivalent detection circuit, it is easy to know that Therefore and since the short - circuit complex impedance is the complex impedance from the high - voltage side to the low - voltage side, so Z 12 =k 2 Z 21 . Combining the above formulas, finally we get where Z 21 is the complex impedance from the low - voltage side to the high - voltage side of the distribution transformer to be measured. are the power supplies of phases A, B, and C of the distribution transformer to be measured respectively. are the phase voltages of phases A, B, and C of the distribution transformer to be measured respectively.

[0136] In the embodiment of this application, a rigorous formula for calculating the complex impedance from the high - voltage side to the low - voltage side of the distribution transformer to be measured is provided from a mathematical perspective. From the rigor of mathematical logic, the accuracy of the calculated complex impedance from the high - voltage side to the low - voltage side of the distribution transformer to be measured can be ensured. And by preferably showing the above - mentioned expressions, it is convenient for technicians to provide reference, understanding, calculation, etc. In addition, by using the above - mentioned formula to calculate the complex impedance from the high - voltage side to the low - voltage side of the distribution transformer to be measured, an accurate measurement result can be obtained simply and efficiently.

[0137] In order to better reflect the technical effects brought by this method of this application, this application will be verified through simulation.

[0138] This application is applicable to any series of distribution transformers. Since there are many series of distribution transformer products, for example, S9, S9-M, S10-M, S11-M series enclosed oil-immersed transformers, SCB8, SC(B)9, SCR-10 series encapsulated coil dry-type transformers. Therefore, this application arbitrarily selects the S11-M-200 / 10 type distribution transformer as the distribution transformer for verification and constructs a corresponding transformer simulation model.

[0139] Set the rated capacity of the transformer simulation model to 200 kVA, the connection group to Dyn11, the rated voltage on the high-voltage side to 10 kV, the rated voltage on the low-voltage side to 0.4 kV, the load loss to 2.6 kW, the short-circuit impedance to 4%, and the load to 10 Ω for phase A, 5 Ω for phase B, and 10 Ω for phase C.

[0140] According to the above settings, through the transformer simulation model, the short-circuit reactance from the high-voltage side to the low-voltage side is 20 Ω (20 Ω for each phase), the short-circuit resistance from the high-voltage side to the low-voltage side is 6.5 Ω (6.5 Ω for each phase), and the rated voltage ratio from the high-voltage side to the low-voltage side is 25.

[0141] When there is no fault in the simulation of the transformer simulation model, the synchronous measured zero-sequence voltage vector is 0.082 + i0.245 V, and the neutral line current vector is 23.015 - i0.221 A. Execute this application for calculation, and the calculated complex impedance from the high-voltage side to the low-voltage side is 6.5 + i20 Ω, that is, the short-circuit reactance is 20 Ω and the short-circuit resistance is 6.5 Ω. Further calculation shows that the load loss of the distribution transformer is 2.6 kW and the short-circuit voltage is 4%, which is consistent with the short-circuit reactance of 20 Ω, short-circuit resistance of 6.5 Ω, load loss of 2.6 kW, and short-circuit voltage of 4% obtained from the above settings of the distribution transformer simulation model, indicating that there is no fault.

[0142] When a fault occurs in the simulation of the transformer simulation model, the synchronous measured zero-sequence voltage vector is 0.0558 + i0.261 V, and the neutral line current vector is 22.999 - i0.2254 A. Execute this application for calculation, and the calculated complex impedance from the high-voltage side to the low-voltage side is 4.3 + i21.3 Ω, that is, the short-circuit reactance is 21.3 Ω and the short-circuit resistance is 4.3 Ω. Further calculation shows that the load loss of the distribution transformer is 1.72 kW and the short-circuit voltage is 4.26%, which is inconsistent with the short-circuit reactance of 20 Ω, short-circuit resistance of 6.5 Ω, load loss of 2.6 kW, and short-circuit voltage of 4% obtained from the above settings of the distribution transformer simulation model, indicating that a fault has occurred.

[0143] It can be verified that this method of the present application only needs to simply synchronously measure two variables, namely the zero-sequence voltage vector and the neutral line current vector, on the low-voltage side of the distribution transformer to achieve online monitoring, without the need for other variables, and can well solve the problems existing in the prior art.

[0144] The present application also provides a computer-readable storage medium in a third aspect, storing a computer program, which, when executed by a controller, causes the controller to execute a method for online synchronous vector monitoring of electrical parameters of a distribution transformer in the complex domain in the above method embodiment.

[0145] The present application also provides a computer device in a fourth aspect, including a memory and a controller. The memory stores a computer program, which, when executed by the controller, causes the controller to execute a method for online synchronous vector monitoring of electrical parameters of a distribution transformer in the complex domain in the above method embodiment.

[0146] Figure 9 The internal structure diagram of the computer device in some embodiments is shown. The computer device may specifically be a terminal, a server, or a gateway. As Figure 9 shown, the computer device includes a controller, a memory, and a network interface connected through a system bus.

[0147] Among them, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program, which, when executed by the controller, may cause the controller to implement each step in the above method embodiment. The internal memory may also store a computer program, which, when executed by the controller, may cause the controller to execute each step in the above method embodiment. Those skilled in the art can understand that Figure 9 the structure shown in

[0148] is only a block diagram of some parts of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0149] Among them, any reference to a memory, storage, database, or other medium used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0150] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0151] The above embodiments only represent several implementation manners of this application, and their descriptions are relatively specific and detailed. However, it should not be construed as a limitation on the patent scope of this application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of the patent of this application shall be subject to the appended claims.

Claims

1. An on-line synchronous vector monitoring device for electrical parameters of a distribution transformer in the complex number domain, characterized in that, The device includes a high-precision synchronous vector measurement acquisition module and a controller; The high-precision synchronous vector measurement acquisition module is connected to the controller; The high-precision synchronous vector measurement acquisition module is used to be respectively connected to the neutral line of the low-voltage side of the distribution transformer to be measured and the three-phase phase lines at the outlet, and is used to measure and synchronously acquire the zero-sequence voltage vector and the neutral line current vector of the low-voltage side of the distribution transformer to be measured; The controller is used to determine the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector, so as to determine the load loss and short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance.

2. The device according to claim 1, characterized in that The controller is also used to determine the complex impedance from the high-voltage side to the low-voltage side of the distribution transformer to be measured according to the rated voltage ratio from the high-voltage side to the low-voltage side of the distribution transformer to be measured, the zero-sequence voltage vector and the neutral line current vector, and use the complex impedance as the short-circuit complex impedance.

3. The device according to claim 1, wherein The high-precision synchronous vector measurement acquisition module includes a voltage transformation module, a current sensing module and a synchronous vector precise acquisition module; The voltage transformation module and the current sensing module are both connected to the synchronous vector precise acquisition module, and the synchronous vector precise acquisition module is connected to the controller; The voltage transformation module is used to be respectively connected to the neutral line of the low-voltage side of the distribution transformer to be measured and the three-phase phase lines at the outlet, and the current sensing module is used to be connected to the neutral line of the low-voltage side of the distribution transformer to be measured; The voltage transformation module is used to measure the zero-sequence voltage vector; The current sensing module is used to measure the neutral line current vector; The synchronous vector precise acquisition module is used to synchronously acquire the zero-sequence voltage vector and the neutral line current vector.

4. The device according to claim 3, characterized in that, The voltage transformation module includes a first impedance, a second impedance and a third impedance; One end of the first impedance and one end of the second impedance are both connected to one end of the third impedance to form a first impedance access end; The other end of the first impedance, the other end of the second impedance and the other end of the third impedance are respectively used to be connected to the three-phase phase lines at the outlet of the low-voltage side of the distribution transformer to be measured, and the first impedance access end is used to be connected to the neutral line of the low-voltage side of the distribution transformer to be measured.

5. The device according to claim 1, characterized in that The device also includes an imbalance adjustment module; The imbalance adjustment module is used to be respectively connected to the neutral line of the low-voltage side of the distribution transformer to be measured and the three-phase phase lines at the outlet; When the voltage amplitude of the zero-sequence voltage vector is less than the start threshold, the imbalance adjustment module is used to adjust the three-phase imbalance degree of the low-voltage side of the distribution transformer to be measured until the voltage amplitude of the zero-sequence voltage vector is greater than or equal to the start threshold.

6. The device according to claim 5, characterized in that The imbalance adjustment module includes a first unbalanced impedance, a second unbalanced impedance, a third unbalanced impedance and a first switching switch; One end of the first unbalanced impedance and one end of the second unbalanced impedance are both connected to one end of the third unbalanced impedance to form a first unbalanced access end, and the first unbalanced access end is connected to one end of the first switching switch; The other ends of the first unbalanced impedance, the second unbalanced impedance, and the third unbalanced impedance are respectively used to connect to the three-phase phase lines at the low-voltage side outlet of the distribution transformer to be measured, and the other end of the first switching switch is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured; Among them, at least one of the first unbalanced impedance, the second unbalanced impedance, and the third unbalanced impedance is an adjustable unbalanced impedance.

7. The device according to claim 5, characterized in that, The unbalance adjustment module includes a fourth unbalanced impedance, a second switching switch, a third switching switch, and a fourth switching switch; One end of the second switching switch and one end of the third switching switch are both connected to one end of the fourth switching switch to form a second unbalanced end, and the second unbalanced end is connected to one end of the fourth unbalanced impedance; The other ends of the second switching switch, the third switching switch, and the fourth switching switch are respectively used to connect to the three-phase phase lines at the low-voltage side outlet of the distribution transformer to be measured, and the other end of the fourth unbalanced impedance is used to connect to the neutral line of the low-voltage side of the distribution transformer to be measured.

8. An online synchronous vector monitoring method for electrical parameters of a distribution transformer in the complex number domain, characterized in that, The method includes: Obtain the zero-sequence voltage vector and the neutral line current vector at the low-voltage side of the distribution transformer to be measured; Determine the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector; Determine the load loss and short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance.

9. The method according to claim 8, wherein The determining the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral line current vector includes: Obtain the rated voltage ratio of the high-voltage side to the low-voltage side of the distribution transformer to be measured; Determine the complex impedance of the high-voltage side to the low-voltage side of the distribution transformer to be measured according to the rated voltage ratio, the zero-sequence voltage vector, and the neutral line current vector; Take the complex impedance as the short-circuit complex impedance.

10. The method according to claim 9, characterized in that, The determining the complex impedance of the high-voltage side to the low-voltage side of the distribution transformer to be measured according to the rated voltage ratio, the zero-sequence voltage vector, and the neutral line current vector includes: Using the formula to determine the complex impedance; Among them, Z 12 is the complex impedance, is the zero-sequence voltage vector, is the neutral line current vector, and k is the rated voltage ratio.

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