A control system and control method for transformer heavy load and overload balancing management

Abstract

The invention discloses a control system and a control method for transformer overload balancing management. The input ends of the main current detector and the main voltage detector are connected to the main transformer, and the main current detector and the main voltage detector are connected to the main real-time data operator; the input ends of the auxiliary current detector and the auxiliary voltage detector are connected to the auxiliary transformer, and the auxiliary current detector and the auxiliary voltage detector are connected to the auxiliary real-time data operator; the main real-time data operator and the auxiliary real-time data operator are connected to the system unified operation unit, and the system unified operation unit is connected to the main parameter setter and the system closed-loop controller; the system closed-loop controller is connected to the system output instruction controller, and the system output instruction controller is respectively connected to the main dynamic current compensator and the auxiliary dynamic current compensator; the main dynamic current compensator is connected to the main transformer power grid, and the auxiliary dynamic current compensator is connected to the auxiliary transformer power grid. It is used to solve the problems of transformer overload, transformer overload, and insufficient transformer capacity.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronics, and in particular relates to a control system and a control method for transformer heavy load and overload balancing management. Background Art

[0002] With the deepening adjustment of social and economic structure and the improvement of people's quality of life, electricity consumption has shown a continuous growth trend. Especially in the stage of rapid industrialization and urbanization, the electricity load of industrial production and residents' daily life has increased significantly, resulting in the distribution transformers with fixed original design capacity facing the challenge of being unable to effectively cope with the increasing load pressure. Especially during the peak period of seasonal electricity consumption (such as air conditioning and cooling in summer and electric heating in winter), the overload condition of transformers is particularly prominent. In addition, there are cases where some transformers have too much output and some transformers have too little output.

[0003] To address this problem, the current main domestic solutions are: replace the transformer with a transformer with large capacity and strong load capacity; add transformers to increase transformer capacity and load capacity. However, both current solutions have certain disadvantages. Transformer replacement requires large investment, takes a long time, and requires coordinated power outages, which makes maintenance more difficult. In addition, if the replaced transformer continues to have problems such as overload and overload due to the increase in load, the cost of maintenance and transformation will increase further. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a control system and a control method for transformer heavy load and overload balancing management in view of the deficiencies in the above-mentioned prior art, so as to solve the technical problems of existing transformer heavy load and overload, large and small transformer capacity usage, high transformer replacement cost and inconvenient later maintenance.

[0005] The present invention adopts the following technical solutions: A control system for transformer heavy load and overload balancing management, comprising a main current detector, a secondary current detector, a main voltage detector and a secondary voltage detector; The input ends of the main current detector and the main voltage detector are respectively connected to the main transformer power grid, and the output ends of the main current detector and the main voltage detector are connected to the system unified operation unit via the main real-time data operator to send the main transformer current and voltage sampling data; The input ends of the secondary current detector and the secondary voltage detector are connected to the secondary transformer power grid, and the output ends of the secondary current detector and the secondary voltage detector are connected to the system unified operation unit via the secondary real-time data operator for sending the secondary transformer current and voltage sampling data; The system unified operation unit is connected to the main dynamic current compensator and the auxiliary dynamic current compensator through the system closed-loop controller and the system output instruction controller respectively, the main dynamic current compensator is connected to the main transformer power grid, and the auxiliary dynamic current compensator is connected to the auxiliary transformer power grid, for balancing the transformer power; The system closed-loop controller is also connected to a main parameter setter for performing data and closed-loop operations according to the setting data of the main parameter setter and the calculation data of the system unified operation unit.

[0006] Preferably, the main current detector and the auxiliary current detector are current sampling transformers or Hall current sensors, which are used to sample the current data of the transformer in real time; The main voltage detector and the auxiliary voltage detector are voltage sampling transformers or differential high-voltage sampling circuits with second-order low-pass filtering, which are used to sample the voltage data of the transformer in real time.

[0007] Preferably, the main real-time data operator and the auxiliary real-time data operator transmit the collected real-time voltage and current information to the system unified operation unit via 485 or wireless communication.

[0008] Preferably, the system closed-loop controller and the system unified computing unit are ARM chips. The system closed-loop controller is used to perform closed-loop judgment of active output using PID proportional integral differential control. The system unified computing unit can calculate load current, load power, active current, active power, reactive current and reactive power data based on the real-time current data and real-time voltage data transmitted by the main real-time data operator and the sub-real-time data operator.

[0009] Preferably, the main parameter setter is set using a configuration touch screen or a serial port control screen; it is used to set the system operation judgment threshold and output target parameters, and output them to the system closed-loop controller.

[0010] Preferably, the main dynamic current compensator and the auxiliary dynamic current compensator are PCS equipment active current output devices, and the PCS equipment active current output devices are PCS converter modules, including three-level modular PCS and two-level PCS.

[0011] Another technical solution of the present invention is a control method of a control system for transformer heavy load and overload balancing management, comprising the following steps: respectively sampling the current and voltage information of the main transformer and the auxiliary transformer; According to the current and voltage information of the main transformer and the auxiliary transformer obtained by sampling, as well as the equipment's own information, the load current, load power, active current, active power and reactive current, reactive power data of the main transformer and the auxiliary transformer are calculated; Determine the load rate of the main transformer and the auxiliary transformer based on the load current, load power, active current, active power and reactive current, and reactive power data of the main transformer and the auxiliary transformer, and calculate the active demand output value of the main\auxiliary closed-loop control in combination with the preset balanced power target threshold; The active power output of the main transformer is taken as the current output value, the difference between the required output value and the current output value is calculated as the current deviation value, and the current deviation value is used as the previous deviation value for the next operation; the closed-loop active output value is calculated based on the current deviation value and the previous deviation value based on the preset closed-loop control algorithm; according to the closed-loop active output value, active current is output or absorbed to the grid side of the transformer to achieve transformer heavy load and overload balancing management.

[0012] Preferably, the grid current and voltage, as well as the phase angle α, are sampled by the main and auxiliary transformers to calculate the main transformer grid active current for:

[0013] Main transformer grid reactive current for:

[0014] Main transformer active power for:

[0015] Main transformer reactive power for:

[0016] Main transformer total active power for:

[0017] Main transformer total reactive power for:

[0018] Define the main transformer grid A, B, C currents as I Az ,I Bz ,I Cz , the voltages of the main transformer grids A, B, and C are U Az , U Bz , U Cz , the active current of the main transformer grid is , , the reactive currents of the main transformer grids A, B, and C are , , , the active power of main transformer grid A, B, C are , , , the reactive power of main transformer grid A, B, and C are , the total active power of the main transformer grid is , the total reactive power of the main transformer grid is ; Main transformer grid three-phase active current , and for:

[0019]

[0020]

[0021] The three-phase reactive current of the main transformer grid is:

[0022]

[0023]

[0024] The three-phase active power of the main transformer grid is:

[0025]

[0026]

[0027] The three-phase reactive power of the main transformer grid is:

[0028]

[0029]

[0030] Main transformer grid total active power for:

[0031] Main transformer grid total reactive power for:

[0032] Define the currents of auxiliary transformer grids A, B, and C as I Af ,I Bf、 I Cf , the voltages of the auxiliary transformer grids A, B, and C are U Af , UBf , U Cf , the active current of the auxiliary transformer grid is , , the reactive currents of auxiliary transformer grids A, B, and C are , , , the active power of auxiliary transformer grids A, B, and C are , , , the reactive power of auxiliary transformer grids A, B, and C are , the total active power of the auxiliary transformer grid is , the total reactive power of the auxiliary transformer grid is ; The three-phase active current of the auxiliary transformer grid is:

[0033]

[0034]

[0035] The three-phase reactive current of the auxiliary transformer grid is:

[0036]

[0037]

[0038] The three-phase active power of the auxiliary transformer grid is:

[0039]

[0040]

[0041] The three-phase reactive power of the auxiliary transformer grid is

[0042]

[0043]

[0044] Auxiliary transformer grid total active power for:

[0045] Total reactive power of auxiliary transformer grid for: .

[0047] Preferably, the closed-loop target value of the load factor for:

[0048] in, is the load rate of the main transformer, is the load factor of the auxiliary transformer.

[0049] Preferably, the closed-loop active output value for:

[0050] in, is the proportionality coefficient, is the integration coefficient, is the closed-loop deviation, is the deviation, is the previous deviation.

[0051] Compared with the prior art, the present invention has at least the following beneficial effects: A control system for transformer heavy-load and overload balancing management, the system samples the current and voltage information of the main transformer and the auxiliary transformer respectively; calculates the load current, load power, active current, active power and reactive current, and reactive power data of the main transformer and the auxiliary transformer according to the sampled current and voltage information of the main transformer and the auxiliary transformer, as well as the equipment's own information; determines the load rate of the main transformer and the auxiliary transformer based on the load current, load power, active current, active power and reactive current, and reactive power data of the main transformer and the auxiliary transformer, and calculates the active demand output value of the main\auxiliary closed-loop control in combination with a preset balanced power target threshold; takes the active power output of the main transformer as the current output value, calculates the difference between the demand output value and the current output value as the current deviation value, and takes the current deviation value as the previous deviation value for the next operation; calculates the closed-loop active output value based on the current deviation value and the previous deviation value based on a preset closed-loop control algorithm; outputs or absorbs active current to the grid side of the transformer according to the closed-loop active output value, and realizes transformer heavy-load and overload balancing management.

[0052] Furthermore, the voltage sampling transformer can sample and process the voltage signal in the power system to achieve power measurement and monitoring. It can convert the power signal into an analog output signal to achieve the measurement of voltage and other electrical quantities in the power system.

[0053] Furthermore, the collected real-time voltage and current information is transmitted to the unified operation unit of the system through 485 or wireless communication, in order to sample the power data of different transformers, and then let the unified operation unit of the system perform data analysis and processing.

[0054] Furthermore, the main functions of ARM chips include efficiently processing parallel tasks, reducing power consumption, improving performance and flexibility. It has fast processing speed and capabilities, and is currently a popular choice for data analysis and processing.

[0055] Furthermore, the configuration touch screen or serial port control screen is used for setting because they are easy to operate and can be operated in an intuitive touch mode, so that the operator can operate directly through the touch screen without using input devices such as keyboard or mouse, thereby simplifying the operation process. In addition, they have the advantages of moderate development difficulty, high integration, adaptability to harsh environments, and multiple interfaces.

[0056] Furthermore, the active current output device of the PCS equipment has a high hardware integration, supports inversion and rectification, and can realize bidirectional conversion, that is, it can convert DC into AC, and also convert AC into DC. This enables the PCS equipment to flexibly switch between absorbing power and releasing power according to the needs of the power grid, thereby realizing the regulation of the active power and reactive power of the power grid, which is a good choice for transferring active power in capacity balancing.

[0057] The control method of the control system for transformer heavy-load and overload balancing management is to sample the current and voltage information of the main transformer and the auxiliary transformer respectively; calculate the load current, load power, active current, active power and reactive current, and reactive power data of the main transformer and the auxiliary transformer according to the sampled current and voltage information of the main transformer and the auxiliary transformer, as well as the equipment's own information; determine the load rate of the main transformer and the auxiliary transformer based on the load current, load power, active current, active power and reactive current, and reactive power data of the main transformer and the auxiliary transformer, and calculate the active demand output value of the main\auxiliary closed-loop control in combination with a preset balanced power target threshold; take the active power output of the main transformer as the current output value, calculate the difference between the demand output value and the current output value as the current deviation value, and take the current deviation value as the previous deviation value for the next operation; calculate the closed-loop active output value based on the current deviation value and the previous deviation value based on a preset closed-loop control algorithm; output or absorb active current to the grid side of the transformer according to the closed-loop active output value to achieve transformer heavy-load and overload balancing management.

[0058] In summary, the present invention includes multiple modules with high integration and high usability, and can be suitable for different transformer locations. The main components include a main current detector, a secondary current detector, a main voltage detector, a secondary voltage detector, a main real-time data operator, a system unified operation unit, a secondary real-time data operator, a system closed-loop controller, a system output instruction controller, a main dynamic current compensator, a secondary dynamic current compensator, a main parameter setter, etc. Through the coordination of information sampling, data analysis, control unit, output unit, etc., it is possible to well realize transformer data sampling, load factor output analysis, PCS output control, and finally realize active power transfer, thereby realizing the role of transformer capacity balancing.

[0059] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings to be used in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0061] Figure 1 It is a schematic diagram of the architecture of the transformer overload balancing management control system of the present invention; Figure 2 The figure is a logical schematic diagram of the transformer overload balancing management control system of the present invention.

[0062] Among them: 100. Main current detector; 200. Main voltage detector; 300. Main dynamic current compensator; 400. Auxiliary dynamic current compensator; 500. Auxiliary voltage detector; 600. Auxiliary current detector; 700. Main real-time data operator; 800. System output instruction controller; 900. Auxiliary real-time data operator; 1000. Main parameter setter; 1100. System closed-loop controller; 1200. System unified operation unit. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "one side", "one end", "one side" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0065] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0067] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0068] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0069] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0070] The invention provides a control system and a control method for transformer heavy-load and overload balancing management. The input ends of a main current detector and a main voltage detector are connected to a main transformer (0.4KV side), and the main current detector and the main voltage detector are both connected to a main real-time data operator; the input ends of a secondary current detector and a secondary voltage detector are connected to a secondary transformer (0.4KV side), and the secondary current detector and the secondary voltage detector are both connected to a secondary real-time data operator; the main real-time data operator and the secondary real-time data operator are commonly connected to a system unified operation unit, and the system unified operation unit and a main parameter setter are both connected to a system closed-loop controller; the system closed-loop controller is connected to a system output instruction controller, and the system output instruction controller is respectively connected to a main dynamic current compensator and a secondary dynamic current compensator; the main dynamic current compensator is connected to a main transformer power grid (0.4KV side), and the secondary dynamic current compensator is connected to a secondary transformer power grid (0.4KV side); by balancing the output of two transformers through the invention, a better management effect can be achieved, thereby solving the problems of transformer heavy load, transformer overload, insufficient transformer capacity, etc.

[0071] See also Figure 1 The present invention provides a control system for transformer heavy load and overload balancing management, comprising: a main current detector 100, a main voltage detector 200, a main dynamic current compensator 300, a secondary dynamic current compensator 400, a secondary voltage detector 500, a secondary current detector 600, a main real-time data operator 700, a system output instruction controller 800, a secondary real-time data operator 900, a main parameter setter 1000, a system closed-loop controller 1100, and a system unified operation unit 1200.

[0072] The input end of the main current detector 100 is connected to the main transformer power grid (0.4KV side), the input end of the main voltage detector 200 is connected to the main transformer power grid (0.4KV side), the output ends of the main current detector 100 and the main voltage detector 200 are both connected to the input end of the main real-time data operator 700, and the output end of the main real-time data operator 700 is connected to the input end of the system unified operation unit 1200, which is used to transmit the current and voltage sampling data of the main transformer to the system unified operation unit 1200.

[0073] The input end of the auxiliary current detector 600 is connected to the auxiliary transformer power grid (0.4KV side), the input end of the auxiliary voltage detector 500 is connected to the auxiliary transformer power grid (0.4KV side), the output ends of the auxiliary current detector 600 and the auxiliary voltage detector 500 are both connected to the input end of the auxiliary real-time data operator 900, and the output end of the auxiliary real-time data operator 900 is connected to the input end of the system unified operation unit 1200, which is used to transmit the auxiliary transformer current and voltage sampling data to the system unified operation unit 1200.

[0074] The output end of the system unified operation unit 1200 is connected to the input end of the system closed-loop controller 1100, and the output end of the main parameter setter 1000 is also connected to the input end of the system closed-loop controller 1100; the system closed-loop controller 1100 performs data and closed-loop operations based on the setting data of the main parameter setter 1000 and the calculation data of the system unified operation unit 1200.

[0075] The output end of the system closed-loop controller 1100 is respectively connected to the input end of the main dynamic current compensator 300 and the input end of the auxiliary dynamic current compensator 400. The main dynamic current compensator 300 outputs and the auxiliary dynamic current compensator 400 outputs or absorbs active current, thereby balancing the transformer power.

[0076] In this embodiment, a control system for transformer heavy load and overload balancing management is constructed to manage transformer heavy load, overload, uneven output and other problems. Closed-loop control is used to make the output of two groups of transformers reach the expected value, thereby achieving better management effect, thereby solving the problems of large increase in investment in transformer replacement, difficult maintenance, and uneven use of transformers.

[0077] Specifically, the input end of the main current detector 100 is connected to the main transformer grid (0.4KV side), the input end of the main voltage detector 200 is connected to the main transformer grid (0.4KV side), and the output ends of the main current detector 100 and the main voltage detector 200 are both connected to the input end of the main real-time data operator 700, and the main transformer current and voltage sampling data are transmitted to the main real-time data operator for main transformer sampling data operation. The output end of the main real-time data operator 700 is connected to the input end of the system unified operation unit 1200. After the data is processed, the main transformer current and voltage sampling operation data are transmitted to the system unified operation unit 1200 through a specific communication method. The input end of the auxiliary current detector 600 is connected to the auxiliary transformer grid (0.4KV side), the input end of the auxiliary voltage detector 500 is connected to the auxiliary transformer grid (0.4KV side), and the output ends of the auxiliary current detector 600 and the auxiliary voltage detector 500 are both connected to the input end of the auxiliary real-time data operator 900, and the auxiliary transformer current and voltage sampling data are transmitted to the auxiliary real-time data operator for auxiliary transformer sampling data operation. The output end of the auxiliary real-time data operator 900 is connected to the input end of the system unified operation unit 1200. After the data is processed, the auxiliary transformer current and voltage sampling operation data is transmitted to the system unified operation unit 1200 through a specific communication method. The output end of the system unified operation unit 1200 is connected to the input end of the system closed-loop controller 1100, and the processed main and auxiliary transformer data are transmitted to the closed-loop controller for closed-loop operation. The reason for using a closed loop here is that the closed loop has strong anti-interference ability, high control accuracy, can monitor the state of the controlled object in real time, and adjust according to feedback information to make the system more stable, accurate and reliable. The open loop cannot achieve this effect. Although the open loop can directly perform active compensation based on the sampled active power of the main and auxiliary transformers, the compensation speed is fast, but there is no feedback adjustment, which is easy to cause inaccurate compensation due to sampling deviation or other reasons, and it is ultimately difficult to achieve the governance effect. In the closed-loop controller, the device performs closed-loop operations through the sampled data of the main transformer and the auxiliary transformer, as well as the load rate comparison threshold, load rate target and other data set by the main parameter setter 1000, to control the output of the main dynamic current compensator 300 and the auxiliary dynamic current compensator 400. In this way, the overload, heavy load and other problems of the transformer can be accurately managed through algorithms such as PID or repetitive control, thereby achieving balanced power management of the two transformers.

[0078] In the above embodiment, preferably, the main current detector 100 and the auxiliary current detector 600 are current sampling transformers or Hall current sensors, which are used to sample the current data of the main and auxiliary transformers in real time and are connected before the grid side and the load side of the transformer. The installation direction of the current sampling transformer needs to be: P1 points to the grid side of the transformer, and P2 points to the load electrical equipment side. Three transformers need to be connected to sample the three-phase data of A, B, and C respectively.

[0079] Specifically, according to the nameplates of the main and auxiliary transformers on site, the following parameters need to be set: Host transformer rated power: Host transformer rated power, modified according to actual conditions.

[0080] Slave transformer rated power: Slave transformer rated power, modified according to actual conditions.

[0081] Set threshold: Transformer load rate threshold, modify according to actual site needs.

[0082] Ring width: The fluctuation of transformer load rate threshold, which can be modified according to actual conditions.

[0083] System automatic start and stop setting time: Transformer load factor is greater than or less than the threshold delay time.

[0084] Main and auxiliary current sampling ratio: Two sets of transformers are used on site, which are connected to the main cabinet equipment and auxiliary cabinet equipment respectively. According to the actual transformer ratio, they are set to 500 and 500 respectively.

[0085] In the above implementation, preferably, the main voltage detector 200 and the auxiliary voltage detector 500 are voltage sampling transformers or differential high-voltage sampling circuits with second-order low-pass filtering, which are used to sample the voltage data of the transformer in real time.

[0086] In the above embodiment, preferably, the system unified computing unit 1200 is an ARM chip with fast data processing computing capabilities, which is used to perform fast calculations on the real-time current data and real-time voltage data transmitted by the main real-time data operator 700 and the sub-real-time data operator 900, and to calculate data such as load current, load power, active current, active power, reactive current, and reactive power.

[0087] In the above implementation, preferably, the main parameter setter 1000 is set using a configuration touch screen or a serial port control screen; The main parameter setter 1000 is used to set parameters such as the system operation judgment threshold and output target, and output these parameters to the system closed-loop controller 1100; Specifically, the main parameter setter 1000 performs human-computer interaction through a touch screen controller on the display interface, wherein the parameters that can also be viewed and set include: Active mode, frequency lower limit, frequency upper limit, midpoint control enable, closed-loop proportional coefficient, closed-loop integral coefficient, closed-loop current deviation, closed-loop last deviation, closed-loop output, working mode, voltage regulation target, total active power of host load, total active power of slave load, total active power of host grid, total active power of slave grid, total output active power, system start detection timing, system stop detection timing, etc.

[0088] The meanings of the specific parameters are as follows: Active mode: Active working mode, divided into current mode and power mode, 0 represents current mode, 1 represents power mode.

[0089] Frequency lower limit: Set the minimum operating frequency setting, generally set to 48.50Hz.

[0090] Frequency upper limit: Set the maximum operating frequency, generally set to 51.50Hz.

[0091] Midpoint control enable: whether to enable the midpoint control function, 0 is off, 1 is on.

[0092] Closed-loop proportional coefficient: Closed-loop control, proportional coefficient, setting range 0~1, default 0.1, if oscillation occurs, you can reduce this value.

[0093] Closed-loop integral coefficient: Closed-loop control, integral coefficient, setting range 0~1, default 0.1, if oscillation occurs, you can reduce this value.

[0094] Closed-loop current deviation: closed-loop control, current deviation, the difference between the sample and the target value.

[0095] Closed-loop last deviation: Closed-loop control, last deviation, the difference between the last sampling and the target value.

[0096] Working mode: device working mode, 0 is normal mode, 1 is power-on self-start mode.

[0097] Voltage stabilization target: DC side voltage target value after the equipment is in operation.

[0098] Main load total active power: total active power of main transformer load.

[0099] Total active power of slave load: total active power of slave transformer load.

[0100] Main power grid total active power: the total active power of the main transformer grid.

[0101] Total active power of slave grid: total active power of slave transformer grid.

[0102] Total output active power: system output active power.

[0103] System startup detection timing: When the system reaches the startup conditions and lasts for the system startup detection timing value, it can start normally.

[0104] System stop detection timing: When the system reaches the stop condition and continues for the system stop detection timing value, it can stop normally.

[0105] In the above implementation, preferably, the main real-time data operator 700 and the sub-real-time data operator 900 transmit the collected real-time voltage and current information to the system unified operation unit 1200 via 485 or wireless communication.

[0106] In the above implementation, preferably, the system closed-loop controller 1100 is an ARM chip with programming and fast data processing computing capabilities, which is used to perform active output closed-loop judgment using a PID proportional-integral-differential control method.

[0107] In the above implementation, preferably, the main dynamic current compensator 300 and the auxiliary dynamic current compensator 400 are PCS equipment active current output devices, and the PCS equipment active current output devices are PCS converter modules, including three-level modular PCS and two-level PCS.

[0108] According to the transformer overload balance management control system disclosed in the above-mentioned embodiment, the voltage data and current data of the main and auxiliary transformers obtained by sampling are transmitted to the system closed-loop controller 1100 after data calculation. The system closed-loop controller 1100 executes the system logic according to the closed loop and parameters set by the main parameter setter 1000, determines whether the load meets the conditions for operating the equipment, and calculates the active closed-loop output. The system closed-loop controller 1100 calculates the system active closed-loop output according to the data obtained by real-time sampling calculation. The calculated closed-loop parameters will first be transmitted to the system output instruction controller 800, and then the system output instruction controller 800 will transmit the data to the main dynamic current compensator 300 and the auxiliary dynamic current compensator 400 through wired or wireless communication. The main and auxiliary dynamic current compensators will output active power according to the output instructions issued by the system, thereby acting on the main and auxiliary transformers.

[0109] See also Figure 2 The present invention also discloses a control method for a transformer overload balance management control system, comprising the following steps: S1, the main current detector 100 samples the current information of the main transformer, and the main voltage detector 200 samples the voltage information of the main transformer; the auxiliary current detector 600 samples the current information of the auxiliary transformer, and the auxiliary voltage detector 500 samples the voltage information of the auxiliary transformer; The main current detector 100 samples the main transformer grid-side A phase current, grid-side B phase current, and grid-side C phase current, which are respectively denoted as IAz ,I Bz、 I Cz The main current detector 100 can be a sampling current sampling transformer or a Hall current sensor. The auxiliary current detector 600 samples the auxiliary transformer grid side A phase current, grid side B phase current, grid side C phase current, respectively denoted as I Af ,I Bf、 I Cf The secondary current detector 600 can be a sampling current sampling transformer or a Hall current sensor.

[0110] The main voltage detector 200 samples the A phase voltage, B phase voltage and C phase voltage of the main transformer grid side, which are denoted as U Az , U bz , U cz The main voltage detector 200 can be a voltage sampling transformer or a differential high-voltage sampling circuit with a second-order low-pass filter. The auxiliary voltage detector 500 samples the A phase voltage, B phase voltage and C phase voltage of the auxiliary transformer grid side, which are respectively denoted as U Af , U Bf , U Cf The secondary voltage detector 500 may be a voltage sampling transformer or a differential high voltage sampling circuit with a second-order low-pass filter.

[0111] S2. Calculate the main and auxiliary transformer grid active current, grid active power, load active current, load active power, grid reactive current, grid reactive power, load reactive current, load reactive power and other data based on the sampled main and auxiliary transformer voltage and current information and the equipment's own information; The grid current and voltage, as well as the phase angle α, are sampled by the main and auxiliary transformers, and the active current of the main transformer grid is calculated according to the formula:

[0112] The reactive current of the main transformer grid is:

[0113] The active power of the main transformer is:

[0114] The reactive power of the main transformer is:

[0115] The total active power of the main transformer is:

[0116] The total reactive power of the main transformer is:

[0117] Define the main transformer grid A, B, C currents as I Az ,I Bz ,I Cz , define the voltages of the main transformer grids A, B, and C as U Az , U Bz , U Cz , the main transformer grid active current is defined as , , define the reactive currents of main transformer grid A, B, and C as , , , define the active power of main transformer grid A, B, C as , , , define the reactive power of main transformer grid A, B, and C as , define the total active power of the main transformer grid as , define the total reactive power of the main transformer grid as .

[0118] The three-phase active current of the main transformer grid is:

[0119] The three-phase reactive current of the main transformer grid is:

[0120] The three-phase active power of the main transformer grid is:

[0121] The three-phase reactive power of the main transformer grid is:

[0122] The total active power of the main transformer grid is:

[0123] The total reactive power of the main transformer grid is:

[0124] Define the currents of auxiliary transformer grids A, B, and C as I Af ,I Bf、 I Cf , define the voltages of the auxiliary transformer grids A, B, and C as U Af , U Bf , U Cf , the active current of the auxiliary transformer grid is defined as , , define the reactive currents of auxiliary transformer grids A, B, and C as , , , define the active power of auxiliary transformer grid A, B, C as , , , define the reactive power of auxiliary transformer grid A, B, and C as , define the total active power of the auxiliary transformer grid as , define the total reactive power of the auxiliary transformer grid as .

[0125] The three-phase active current of the auxiliary transformer grid is:

[0126] The three-phase reactive current of the auxiliary transformer grid is:

[0127] The three-phase active power of the auxiliary transformer grid is:

[0128] The three-phase reactive power of the auxiliary transformer grid is:

[0129] The total active power of the auxiliary transformer grid is:

[0130] The total reactive power of the auxiliary transformer grid is: .

[0132] S3, calculating the required output value of the closed-loop control according to the load rate of the main and auxiliary transformers calculated by the active power of the sampled loads of the main and auxiliary transformers and the preset target threshold; Define the rated power of the main transformer as , the rated power of the auxiliary transformer is defined as , define the load factor of the main transformer as , the auxiliary transformer load factor is defined as ; The load rate of the main transformer is

[0133] The load rate of the auxiliary transformer is

[0134] Define the closed-loop target value of the load factor as , set the closed-loop target value of the load factor to =( + ) 2. This will divide the output of the two transformers equally, making the output of the two transformers the same, thus solving the problem of one transformer being overloaded and the other transformer being underloaded.

[0135] S4. Based on the active power output of the main transformer as the current output value, calculate the difference between the required output value and the current output value as the current deviation value, and use the current deviation value as the previous deviation value for the next operation; calculate the closed-loop active output value based on the current deviation value and the previous deviation value based on a preset closed-loop control algorithm; output or absorb active current to the grid side of the transformer according to the closed-loop active output value.

[0136] Define the closed-loop deviation as , define the last closed-loop deviation as , is the manually set closed-loop target value, and the main transformer load factor is used as the closed-loop feedback. The closed-loop deviation can be calculated as - , the program records the current deviation value each time it is executed and uses it as the previous deviation value for the next operation, recorded as .

[0137] Use closed-loop control PID algorithm to better control the output of the device. Here, PI algorithm is used, and the proportional coefficient is recorded as K P , the integral coefficient is recorded as K I , the proportional coefficient and integral coefficient are set by the main parameter setter, then

[0138] in, is the deviation, is the previous deviation.

[0139] At this time That is, the active power that the final PCS device needs to output, and then a closed-loop limiting judgment is performed, using the closed-loop active output value and the actual capacity of the device to make a judgment. When the output is greater than the maximum device capacity, the limited output active power is the size of the device capacity. After limiting, the closed-loop active power is output, and then the program judgment ends.

[0140] Preferably, the load rates calculated by the main transformer and the auxiliary transformer are compared with the set threshold value. When either the load rate of the main transformer or the load rate of the auxiliary transformer is greater than the set threshold value and lasts for the set self-start time, the system starts to run, starts closed-loop operation, and then starts active power output. When the load rate of the main transformer and the load rate of the auxiliary transformer are both less than the set threshold value and last for the set self-stop time, the system stops running, clears the output of the closed-loop operation, and the device no longer outputs active power.

[0141] The closed-loop active output value is compared with the capacity of the PCS equipment. When the closed-loop active output value is greater than the equipment capacity, the closed-loop active output value is limited to the equipment capacity.

[0142] In the specific implementation process, before the on-site treatment during on-site use, two transformers were selected and the transformer data was observed. It was known that the rated power of the main transformer was 800kW and the rated power of the auxiliary transformer was 800kW. According to the on-site meter, the maximum active power of the main transformer can reach 750kW, and the load rate reaches 93%, which is a serious overload situation. The maximum active power of the auxiliary transformer can only reach 300kW, and the load rate is only 37%. Therefore, these two transformers were selected for the transformation plan.

[0143] From the transformer data, we can see that the closed-loop target threshold is set to (93%+37%) / 2=65%. Setting the closed-loop target to 65% is the best option. However, when the load changes, the target does not change, and the following effect is not ideal. Therefore, the closed-loop target threshold is directly changed to automatic calculation and setting. When the transformer load rate changes, the target also changes accordingly.

[0144] The system self-start time and system self-stop time are set to 60 seconds, and the system start and stop threshold is set to 40%. When the load rate of any transformer exceeds 40%, the system will start to work. The compensation equipment of the main and auxiliary cabinets will manage the two transformers according to the results of the closed-loop output, absorb the power on the side of the transformer with a high load rate, and then transfer it to the side of the transformer with a low load rate and release it. In this process, according to the law of conservation of energy, the equipment does not generate power for no reason, but only transfers the power of the transformer with a high load rate to the side of the transformer with a low load rate, so that the transformer with a high load rate reduces the load active power, and the transformer with a low load rate increases the load active power. In this way, the two transformers can be well utilized at the same time, one using unsaturated and unbalanced output, and the other is overloaded, thereby avoiding and managing the problem of transformer overload.

[0145] After the mutual voltage and current detection and communication wiring of the main and auxiliary equipment on site were completed, the controller data was observed and the necessary parameters were set. The rated power of the main transformer and the cluster transformer were both set to 800kW, the self-start and stop threshold was set to 40%, and the self-start and self-stop time were set to 60 seconds. At this time, since the load was not at the maximum time, it was observed that the active power of the main transformer was 600kW and the load rate was 75%. The active power of the auxiliary transformer was 200kW and the load rate was 25%. The controller data was completely consistent with the transformer meter data, indicating that the wiring was accurate.

[0146] It can be seen that the closed-loop target value of the controller has been automatically set to 50%. The closed-loop parameters of the transformer overload balance management control system are set according to the actual situation on site. The closed-loop proportional coefficient is set to 0.1, and the closed-loop integral coefficient is set to 0.1. The reason for setting a smaller value here is to avoid overshoot and output abnormality. The coefficient can be adjusted at any time according to the actual situation.

[0147] After the parameters are set, turn on the automatic start and stop enable button, and you can observe that the self-start timing starts to accumulate. When it accumulates to 60 seconds, the treatment equipment under the main and auxiliary transformers starts to run, and the closed loop also starts to operate. After a few seconds, we saw that the active power of the main transformer meter dropped to 400kW, and the active power of the slave transformer increased to 400kW. The load rate of the main and slave transformers was also maintained at 50%. We could see that the main transformer compensation equipment absorbed 200kW of active power, while the slave transformer compensation equipment output 200kW of active power. The power of the main transformer with a high load rate was transferred to the slave transformer, and the output was balanced. The whole method achieved good governance effect. Subsequent observations showed that under the maximum load condition, the whole device also operated well, and was able to balance the output of the two transformers, achieving good governance effect.

[0148] To sum up, the control system and control method for transformer heavy load and overload balancing management of the present invention can achieve a good compensation effect and effectively solve the problems of large investment in transformer heavy load and overload management, difficult maintenance, and difficult construction of transformer replacement.

[0149] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A control system for transformer overload balancing management, characterized in that: It comprises a main current detector (100), a secondary current detector (600), a main voltage detector (200) and a secondary voltage detector (500); The input ends of the main current detector (100) and the main voltage detector (200) are respectively connected to the main transformer power grid, and the output ends of the main current detector (100) and the main voltage detector (200) are connected to the system unified operation unit (1200) via the main real-time data operator (700) for sending the main transformer current and voltage sampling data; The input ends of the secondary current detector (600) and the secondary voltage detector (500) are connected to the secondary transformer power grid, and the output ends of the secondary current detector (600) and the secondary voltage detector (500) are connected to the system unified operation unit (1200) via the secondary real-time data operator (900) for sending the secondary transformer current and voltage sampling data; The system unified operation unit (1200) is respectively connected to the main dynamic current compensator (300) and the auxiliary dynamic current compensator (400) via the system closed-loop controller (1100) and the system output command controller (800), the main dynamic current compensator (300) is connected to the main transformer power grid, and the auxiliary dynamic current compensator (400) is connected to the auxiliary transformer power grid, for balancing transformer power; The system closed-loop controller (1100) is also connected to a main parameter setter (1000) for performing data and closed-loop operations according to the setting data of the main parameter setter (1000) and the calculation data of the system unified operation unit (1200).

2. The transformer overload balancing control system according to claim 1 is characterized in that: The main current detector (100) and the auxiliary current detector (600) are current sampling transformers or Hall current sensors, and are used to sample the current data of the transformer in real time; The main voltage detector (200) and the auxiliary voltage detector (500) are voltage sampling transformers or differential high-voltage sampling circuits with second-order low-pass filtering, and are used to sample voltage data of the transformer in real time.

3. The control system for transformer heavy load and overload balancing management according to claim 1 is characterized in that: The main real-time data operator (700) and the auxiliary real-time data operator (900) transmit the collected real-time voltage and current information to the system unified operation unit (1200) via 485 or wireless communication.

4. The control system for transformer overload balancing management according to claim 1 is characterized in that: The system closed-loop controller (1100) and the system unified operation unit (1200) are ARM chips. The system closed-loop controller (1100) is used to perform active output closed-loop judgment using a PID proportional integral differential control method. The system unified operation unit (1200) can calculate load current, load power, active current, active power, reactive current and reactive power data based on real-time current data and real-time voltage data transmitted by the main real-time data operator (700) and the auxiliary real-time data operator (900).

5. The control system for transformer heavy load and overload balancing management according to claim 1 is characterized in that: The main parameter setter (1000) is set using a configuration touch screen or a serial port control screen; it is used to set the system operation judgment threshold and output target parameters, and output them to the system closed-loop controller (1100).

6. The transformer overload balancing control system according to claim 1 is characterized in that: The main dynamic current compensator (300) and the auxiliary dynamic current compensator (400) are PCS equipment active current output devices, and the PCS equipment active current output devices are PCS converter modules, including three-level modular PCS and two-level PCS.

7. The control method of the control system for transformer heavy load and overload balancing management according to any one of claims 1 to 6, characterized in that: The following steps are involved: respectively sampling the current and voltage information of the main transformer and the auxiliary transformer; According to the current and voltage information of the main transformer and the auxiliary transformer obtained by sampling, as well as the equipment's own information, the load current, load power, active current, active power and reactive current, reactive power data of the main transformer and the auxiliary transformer are calculated; Determine the load rate of the main transformer and the auxiliary transformer based on the load current, load power, active current, active power and reactive current, and reactive power data of the main transformer and the auxiliary transformer, and calculate the active demand output value of the main\auxiliary closed-loop control in combination with the preset balanced power target threshold; The active power output of the main transformer is taken as the current output value, the difference between the required output value and the current output value is calculated as the current deviation value, and the current deviation value is used as the previous deviation value for the next operation; the closed-loop active output value is calculated based on the preset closed-loop control algorithm using the current deviation value and the previous deviation value; According to the closed-loop active output value, active current is output or absorbed to the grid side of the transformer to achieve balanced management of transformer heavy load and overload.

8. The control method of the transformer overload balance management control system according to claim 7 is characterized in that: The grid current and voltage are sampled by the main and auxiliary transformers, as well as the phase angle α, to calculate the main transformer grid active current for: Main transformer grid reactive current for: Main transformer active power for: Main transformer reactive power for: Main transformer total active power for: Main transformer total reactive power for: Define the main transformer grid A, B, C currents as I Az ,I Bz、 I Cz , the voltages of the main transformer grids A, B, and C are U Az , U Bz , U Cz , the active current of the main transformer grid is , , the reactive currents of the main transformer grids A, B, and C are , , , the active power of main transformer grid A, B, C are , , , the reactive power of main transformer grid A, B, and C are , the total active power of the main transformer grid is , the total reactive power of the main transformer grid is ; Main transformer grid three-phase active current , and for: The three-phase reactive current of the main transformer grid is: The three-phase active power of the main transformer grid is: The three-phase reactive power of the main transformer grid is: Main transformer grid total active power for: Main transformer grid total reactive power for: Define the currents of auxiliary transformer grids A, B, and C as I Af ,I Bf、 I Cf , the voltages of the auxiliary transformer grids A, B, and C are U Af , U Bf , U Cf , the active current of the auxiliary transformer grid is , , the reactive currents of auxiliary transformer grids A, B, and C are , , , the active power of auxiliary transformer grids A, B, and C are , , , the reactive power of auxiliary transformer grids A, B, and C are , the total active power of the auxiliary transformer grid is , the total reactive power of the auxiliary transformer grid is ; The three-phase active current of the auxiliary transformer grid is: The three-phase reactive current of the auxiliary transformer grid is: The three-phase active power of the auxiliary transformer grid is: The three-phase reactive power of the auxiliary transformer grid is Auxiliary transformer grid total active power for: Total reactive power of auxiliary transformer grid for: 。 9. The control method of the transformer overload balance management control system according to claim 7 is characterized in that: Load factor closed loop target value for: in, is the load rate of the main transformer, is the load factor of the auxiliary transformer.

10. The control method of the transformer overload balance management control system according to claim 7, characterized in that: Closed loop active output value for: in, is the proportionality coefficient, is the integration coefficient, is the closed-loop deviation, is the deviation, is the previous deviation.

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