A voltage transformer accuracy test measurement and control device

Abstract

The application relates to the technical field of power equipment, in particular to a voltage transformer accuracy test measurement and control device, which comprises a precision transformer module, a data acquisition card, a mainboard, a winding switching module, a load switching module group and a computer; the winding input end of the precision transformer module is connected with multiple measured secondary windings of a measured voltage transformer, the winding output end of the precision transformer module is connected with the load switching module group, and the signal output end of the precision transformer module is connected with the data acquisition card; the data acquisition card is connected with the computer and the mainboard respectively; the signal output end of the mainboard is connected with the winding switching module and the load switching module group respectively, and the winding input end of the winding switching module is connected with multiple standard secondary windings of a standard voltage transformer. Through the scheme, the computer can control the switching of the standard transformer and the secondary windings of the measured transformer in the test process by using the digital port of the data acquisition card, and the size of the load connected with the secondary windings of the measured transformer is controlled and measured.

Description

Technical Field

[0001] This invention relates to the field of power equipment technology, specifically to a voltage transformer accuracy testing and control device. Background Technology

[0002] The accuracy test of a voltage transformer involves comparing the secondary output voltage of the voltage transformer under test with that of a standard voltage transformer using a transformer calibrator, and measuring the ratio error and phase error. Voltage transformers typically have multiple (currently up to five) secondary windings, including a measuring winding, a protection winding, and a residual voltage winding. During the test, the error of each secondary winding must be measured.

[0003] Currently, most voltage transformer manufacturers conduct accuracy tests by manually switching the secondary windings of the voltage transformer under test (TDT) and the standard voltage transformer. This involves manually changing the load on the secondary windings and manually recording the test data. Switching between the TDT and standard secondary windings requires disconnecting the test power supply before rewiring, making the process cumbersome and time-consuming. Furthermore, damage to the voltage load box or changes in its parameters during use are difficult to detect in a timely manner, leading to distorted test results. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a voltage transformer accuracy testing and control device, comprising a precision transformer module, a data acquisition card, a motherboard, a winding switching module, a load switching module group, and a computer. The load switching module group includes multiple load switching modules, with each load switching module corresponding to one secondary winding under test.

[0005] The winding input terminal of the precision transformer module is connected to multiple tested secondary windings of the voltage transformer under test; the winding output terminal of the precision transformer module is connected to the load switching module group; and the signal output terminal of the precision transformer module is connected to the data acquisition card. The data acquisition card is connected to the computer and the motherboard respectively. The signal output terminal of the motherboard is connected to the winding switching module and the load switching module group respectively. The winding input terminal of the winding switching module is connected to multiple standard secondary windings and multiple tested secondary windings of the standard voltage transformer respectively.

[0006] The precision transformer module is used to convert the voltage and current of each measured secondary winding according to a set ratio, and send the converted voltage and current signals to the data acquisition card.

[0007] The computer is used to acquire the voltage and current signals of each of the tested secondary windings through a data acquisition card, and to monitor the load value connected to each of the tested secondary windings in real time.

[0008] The computer is further configured to determine the target secondary winding under test, the target standard secondary winding, and the target load value corresponding to the target secondary winding under test according to a preset test procedure; generate control signals and address signals corresponding to the winding switching module and each module in the load switching module corresponding to the target secondary winding under test; and send the generated control signals and address signals to the motherboard. For each winding switching module, the address signal represents the identifier corresponding to the current secondary winding pair; for each load switching module, the address signal represents the identifier corresponding to the load switching module; for each load switching module and winding switching module, the control signal includes the current target load value of the load switching module, as well as the identifier of the current target secondary winding under test and the identifier of the current target standard secondary winding.

[0009] The motherboard is used to control the on / off state of each relay in the winding switching module according to the identifier of the current target tested secondary winding and the identifier of the current target standard secondary winding, so as to determine the current target tested secondary winding and the current target standard secondary winding; and according to the address signal, to control the load value connected to the target tested secondary winding through the load switching module corresponding to the address signal, so that the load value connected to the current target tested secondary winding is the current target load value.

[0010] Technical effects:

[0011] The voltage transformer accuracy test and control device provided by this invention, during operation, converts the voltage and current of the secondary winding under test through a precision transformer module and inputs them to a data acquisition card. The data acquisition card collects the voltage and current signals and sends them to a computer. The computer analyzes and calculates the received voltage and current signals to obtain the load value and power factor connected to each secondary winding of the voltage transformer under test, thereby realizing real-time monitoring of the secondary load in the voltage transformer accuracy test. Based on the technical requirements for setting the test procedure and test parameters, the device automatically controls the sequence according to the predetermined test procedure, automatically switches the standard voltage and the secondary winding under test, and automatically controls the load connected to each secondary winding under test, thus achieving automatic control of the voltage transformer accuracy test.

[0012] Furthermore, it also includes a voltage load box group, which includes a number of voltage load boxes for no less than a plurality of the measured secondary windings. The load unit in each voltage load box is led out through a connector so as to control the load corresponding to the corresponding voltage load box through the connector.

[0013] Using this scheme, the switching of the load value connected to the secondary winding under test can be achieved by using a number of voltage load boxes with no fewer than a number of secondary windings under test.

[0014] Furthermore, the aforementioned precision transformer module includes a number of precision transformer groups not less than a plurality of the measured secondary windings.

[0015] With this approach, since there are usually no more than five secondary windings under test, using a number of precision transformer groups that are no less than the number of secondary windings under test can ensure that the voltage and current of each secondary winding under test are converted.

[0016] Furthermore, each precision transformer group includes a precision voltage transformer and a precision current transformer.

[0017] Using this scheme, the voltage of the secondary winding of the voltage transformer under test can be detected by a precision voltage transformer, and the current of the secondary winding of the voltage transformer under test can be detected by a precision current transformer.

[0018] Furthermore, the motherboard includes a signal input connector, which is connected to the digital output terminal of the data acquisition card.

[0019] Using this solution, the signals from the data acquisition card can be transmitted to the motherboard via a signal connector.

[0020] Furthermore, it also includes a current transformer calibrator, wherein the voltage output terminal of the winding switching module is connected to the voltage input terminal of the current transformer calibrator, and the computer is connected to the current transformer calibrator.

[0021] Using this method, the current transformer calibrator can compare the input standard voltage and the measured voltage to measure the ratio error, phase error, and voltage percentage. The computer reads the measurement result data from the current transformer calibrator.

[0022] Using this scheme, the computer automatically reads the measurement results of the current transformer calibrator according to the test procedure and automatically stores them in the data table, thereby realizing the automatic storage of measurement data.

[0023] Furthermore, the aforementioned computer is also used to analyze and process the voltage and current signals acquired by the data acquisition card, and to calculate and display the load connected to each of the tested secondary windings and the power factor of the load.

[0024] Using this scheme, the computer can also display the load and power factor connected to each tested secondary winding, making it easier for users to monitor the working status of the voltage load box.

[0025] Furthermore, the aforementioned computer is also used to convert a preset target load value into a 7-bit binary control signal according to a preset encoding method.

[0026] Using this scheme, the load value required to be connected to the secondary winding under test can be converted into binary control signals for controlling each load unit in the voltage load box through this encoding method.

[0027] Furthermore, the aforementioned preset test procedure includes a preset test sequence, which comprises multiple test sequences consisting of state values ​​corresponding to each of the multiple control quantities. The multiple control quantities include an accuracy level, a winding identifier of the secondary winding under test, a load value, and a measured voltage. The state value corresponding to the accuracy level includes a state value corresponding to the measurement level and a state value corresponding to the protection level. The winding identifier includes state values ​​corresponding to multiple winding identifiers. The load value includes state values ​​corresponding to multiple load values. The measured voltage includes state values ​​corresponding to multiple measured voltages. For each test sequence, the test sequence includes one state value corresponding to each of the control quantities.

[0028] When the aforementioned computer determines the target secondary winding under test, the target standard secondary winding, and the target load value corresponding to the target secondary winding under test according to the preset test procedure, it is specifically used for:

[0029] According to the preset test sequence, the target tested secondary winding, the target standard secondary winding, and the target load value corresponding to the target tested secondary winding are determined.

[0030] Using this scheme, the tested secondary winding and the standard secondary winding can be automatically switched by pre-setting the test sequence, and the target load value corresponding to the tested secondary winding can be switched at the same time. The sequence of the pre-set test sequence is clearly expressed and easy to modify, without the need for complex condition judgments.

[0031] Furthermore, the aforementioned pre-defined test sequence is represented by a 4-dimensional array constant.

[0032] This approach uses a 4-dimensional array constant to represent the preset test order, making the preset test order clearer, more intuitive, and easier to modify. Attached Figure Description

[0033] Figure 1 This is a connection block diagram of the components in a voltage transformer accuracy testing and control device according to the present invention;

[0034] Figure 2 This is a hardware module diagram of a voltage transformer accuracy testing and control device according to the present invention;

[0035] Figure 3This is a circuit diagram of the precision current transformer module and data acquisition card in this invention;

[0036] Figure 4 This is a circuit diagram of the motherboard in this invention;

[0037] Figure 5 This is a circuit diagram of the winding switching module in this invention;

[0038] Figure 6 This is a circuit diagram of the load switching module in this invention;

[0039] Figure 7 This is a circuit diagram of the voltage load box in this invention;

[0040] Figure 8 This is a schematic diagram of the 4-dimensional array constants corresponding to the preset test sequence in this invention.

[0041] Appendix Figure 1-7 The structures represented by each label are listed below:

[0042] 1. Precision instrument transformer module; 2. Data acquisition card; 3. Main board; 4. Winding switching module; 5. Load switching module group; 6. Voltage load box group; 7. Computer; 8. Power supply module; 9. Instrument transformer calibrator. Detailed Implementation

[0043] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0044] It should be noted that when a part or component is considered to be "connected to," "located on," or "assembled" to another part or component, it can be directly mounted on the other part or component, or it may be located in an intermediate part or component. The terms "left," "right," "upper," "lower," and similar expressions used in this document are for illustrative purposes only.

[0045] In one specific implementation, such as Figure 1-7 As shown, a voltage transformer accuracy test and control device includes a precision transformer module 1, a data acquisition card 2, a motherboard 3, a winding switching module 4, a load switching module group 5, and a computer 7. The load switching module group includes multiple load switching modules, one load switching module corresponds to one tested secondary winding, and one load switching module corresponds to different load values. When the number of tested secondary windings is less than the number of load switching modules, the unused load modules can be left idle.

[0046] The winding input terminal of the aforementioned precision transformer module 1 is connected to multiple tested secondary windings of the voltage transformer under test. The winding output terminal of the precision transformer module 1 is connected to the load switching module group 5. The signal output terminal of the precision transformer module 1 is connected to the data acquisition card 2. The data acquisition card 2 is connected to the computer 7 and the motherboard 3 respectively. The signal output terminal of the motherboard 3 is connected to the winding switching module 4 and the load switching module group 5 respectively. The winding input terminal of the winding switching module 4 is connected to multiple standard secondary windings and multiple tested secondary windings of the standard voltage transformer respectively.

[0047] The aforementioned precision transformer module 1 is used to convert the voltage and current of each measured secondary winding according to a set ratio (such as 150V / 7.07V and 5A / 7.07V), and send the converted voltage and current signals to the data acquisition card 2.

[0048] The computer 7 is used to acquire the voltage and current signals of each of the tested secondary windings through the data acquisition card 2, and to monitor the load value connected to each of the tested secondary windings in real time.

[0049] The computer 7 is further configured to determine, according to a preset test procedure, the target tested secondary winding, the target standard secondary winding, and the target load value corresponding to the target tested secondary winding, and to generate control signals and address signals corresponding to the winding switching module and each module in the load switching module, and to send the generated control signals and address signals to the motherboard 3. For each winding switching module, the address signal represents the identifier corresponding to the current secondary winding pair. For each load switching module, the address signal represents the identifier corresponding to the load switching module. For each load switching module, the control signal includes the current target load value of the load switching module, the identifier of the current target tested secondary winding, and the identifier of the current target standard secondary winding.

[0050] The target load value can be preset. The target tested secondary winding can be any one of the tested secondary windings, and the target standard secondary winding can be any one of the standard secondary windings. During the test of the target tested secondary winding and the target standard secondary winding based on the target load value, control signals and address signals are continuously acquired. When the current target load value in the control signal changes, i.e., the current target load value is not equal to the target load value, the tested secondary winding corresponding to the identifier of the current target tested secondary winding can be taken as the new target tested secondary winding, and the standard secondary winding corresponding to the identifier of the current target standard secondary winding can be taken as the new target standard secondary winding. Then, based on the current target load value, the new target standard secondary winding and the new target tested secondary winding are tested. It should be noted that the new target tested secondary winding may or may not be the target tested secondary winding, and the new target standard secondary winding may or may not be the target standard secondary winding.

[0051] The mainboard 3 is used to control the on / off state of each relay in the winding switching module according to the identifier of the current target tested secondary winding and the identifier of the current target standard secondary winding, so as to determine the current target tested secondary winding and the current target standard secondary winding; and according to the address signal, to control the load value connected to the target tested secondary winding through the load switching module corresponding to the address signal, so that the load value connected to the current target tested secondary winding is the current target load value. At this time, the target tested secondary winding is transformed into the current target tested secondary winding, and the target standard secondary winding is transformed into the current target standard secondary winding.

[0052] The aforementioned current target tested secondary winding can be either the original target tested secondary winding or a new target tested secondary winding. Similarly, the aforementioned current target standard secondary winding can be either the original target standard secondary winding or a new target standard secondary winding. Regardless of whether the current target tested secondary winding is the original target tested secondary winding or a new target tested secondary winding, if the current target tested secondary winding is the original target tested secondary winding, then the test of the original target tested secondary winding will still be performed. If the current target tested secondary winding is a new target tested secondary winding, then the test of the new target tested secondary winding will be performed. The same applies to the current target standard secondary winding, which will not be elaborated further here.

[0053] Specifically, after testing the target secondary winding and the target standard secondary winding, a new target secondary winding and a new target standard secondary winding can be determined according to a preset test procedure. This new set of target secondary windings and standard secondary windings is then tested in the same manner. For example, the target secondary winding and target standard secondary winding include the first target secondary winding and the first standard secondary winding, while the new target secondary winding and the new target standard secondary winding include the second target secondary winding and the second standard secondary winding. The specific target secondary winding and standard secondary winding that the computer 7 needs to test are pre-set in the preset test procedure, and the computer 7 simply executes the test according to the order specified in the preset test procedure. It should be noted that for a set of target tested secondary windings and target standard secondary windings, it is not limited to which of the tested secondary windings and standard secondary windings are included. For example, according to the previous example, the target tested secondary windings and target standard secondary windings include the first tested secondary winding and the first standard secondary winding. Then, the new target tested secondary windings and target standard secondary windings can include the second tested secondary winding and the first standard secondary winding, or it can be the third tested secondary winding and the first standard secondary winding.

[0054] Optionally, the device further includes a voltage load box group 6, which includes a number of voltage load boxes for no less than a plurality of the tested secondary windings. Each load unit in the voltage load box is led out through a connector to control the load corresponding to the corresponding voltage load box through the connector.

[0055] Specifically, for each load switching module, the connection and disconnection of each load unit in the corresponding voltage load box in the voltage load box group 6 are controlled by the on / off state of the relay contacts, thereby controlling the magnitude of the load value connected to the secondary winding of the voltage transformer under test.

[0056] The winding switching module controls the connection of its output standard voltage to one of the two secondary windings of the standard voltage transformer by opening and closing relay contacts, and controls the connection of its output measured voltage to one of the maximum five secondary windings of the measured voltage transformer. This controls the switching of the standard voltage and the switching of the secondary windings of the measured voltage transformer.

[0057] Optionally, the computer 7 described above is also used to analyze and process the voltage and current signals acquired by the data acquisition card 2, calculate and display the load connected to each of the tested secondary windings and the power factor of the load, so as to realize the real-time load monitoring and over-limit alarm functions.

[0058] Optionally, when the computer sends control signals and address signals to the motherboard 3, it can send them in a time-division multiplexing manner. Specifically, it sends the control signal of the first load switching module first, then sends the address signal of the first load switching module, and then sends the control signals and address signals of the second to fifth load switching modules and the winding switching module in sequence.

[0059] Optionally, the aforementioned motherboard 3 includes multiple connector sockets, which are connected together via power lines, address lines, and a data bus. These multiple connector sockets are used to connect various modules in the data acquisition card, winding switching module, and load switching module group.

[0060] Optionally, the motherboard 3 further includes an address decoder and a data buffer. The address decoder is a 3-to-8 decoder, which decodes the 3-bit binary address signal transmitted by the data acquisition card 2 into 8 address signals. After being inverted and buffered, these signals are distributed to the winding switching module 4 and the load switching module via address lines. The data buffer also buffers the data signals sent by the data acquisition card 2 to improve the driving capability, and then transmits them to the winding switching module 4 and each load switching module via the data bus.

[0061] Each load switching module and winding switching module 4 includes a data latch. A jumper selects one of eight address signals as the latch signal to latch the data corresponding to that module on the data bus. The latch's output signal drives a relay coil via a drive circuit, controlling the on / off state of the relay in the winding switching module 4. The data input terminal of the data latch is connected to the data bus, and the latch signal input terminal is connected to one of the eight address lines. Each address line (7-0) represents the address signal of a load switching module. When the control signal of the load switching module appears at the data input terminal of the data latch, a positive pulse immediately appears on its address line. This pulse serves as the latch signal, making the output signal of the data latch's data output terminal the same as and unchanged at the input terminal until the next latch pulse arrives and the input signal changes. The data latch's output signal drives the relay coil via the drive circuit, controlling the on / off state of the relay contacts.

[0062] Optionally, the device also includes a power supply module, the input of which is connected to a 220V, 50Hz AC power supply, and the power supply module outputs a +12V DC power supply to provide working power for the main board 3, the load switching module group 5, and the winding switching module 4.

[0063] Optionally, the load switching module group 5 includes a number of load switching modules not less than a plurality of tested secondary windings.

[0064] Optionally, the aforementioned computer 7 is further configured to convert the target load value in the control signal into a 7-bit binary control signal according to a preset encoding method. The 7-bit binary control signal, from the most significant bit 6 to the least significant bit 0, corresponds to the seven load units of the load box: 80VA, 40VA, 20VA, 10VA, 5VA, 2.5VA, and 1.25VA, respectively.

[0065] Optionally, when the computer 7 converts the target load value in the control signal into a 7-bit binary control signal according to a preset encoding method, it specifically performs the following steps: First, divide the load value (target load value) by 10, process the remainder and quotient to obtain the lower 3 decimal bits and the higher 4 decimal bits; multiply the remainder by 0.8 and round down by 4 bits including 5 bits; if the remainder after rounding is less than 8, then make the lower 3 decimal bits equal to the remainder after rounding and set the carry value to 0; otherwise, make the lower 3 decimal bits equal to 0 and set the carry value to 1; the higher 4 decimal bits are equal to the quotient plus the carry value obtained above, convert the lower 3 decimal bits and the higher 4 decimal bits into lower 3 binary bits and higher 4 binary bits respectively, and then concatenate them into a 7-bit binary number with the higher 4 binary bits on the left and the lower 3 binary bits on the right. This 7-bit binary number is the required binary control signal.

[0066] As an example, for instance, a target load value of 35VA would be converted into a binary control signal of 0011100 using the encoding method described above.

[0067] Optionally, the above-mentioned preset test process includes a preset test sequence, which includes multiple test sequences composed of state values ​​corresponding to each of the multiple control quantities. The multiple control quantities include an accuracy level, a winding identifier of the secondary winding under test, a load value, and a measured voltage. The state value corresponding to the accuracy level includes a state value corresponding to the measurement level and a state value corresponding to the protection level. The winding identifier includes state values ​​corresponding to multiple winding identifiers. The load value includes state values ​​corresponding to multiple load values. The measured voltage includes state values ​​corresponding to multiple measured voltages. For each test sequence, the test sequence includes one state value corresponding to each of the control quantities.

[0068] When the computer 7 determines the target secondary winding under test, the target standard secondary winding, and the load value corresponding to the target secondary winding under test according to the preset test procedure, it is specifically used for:

[0069] According to the preset test sequence, the target secondary winding under test, the target standard secondary winding, and the load value corresponding to the target secondary winding under test are determined.

[0070] The accuracy level has separate state values ​​for the measurement level and the protection level, represented by 0 and 1 respectively. 0 represents the state value for the measurement level, and 1 represents the state value for the protection level. Multiple tested secondary windings can be designated as 1a1n, 2a2n, 3a3n, 4a4n, and dadn, with their respective state values ​​represented by 0, 1, 2, 3, and 4. The load value includes two state values: lower load limit and upper load limit, represented by 0 and 1 respectively. The measured voltage has three state values: 0.8Ur, 1.0Ur, and 1.2Ur (Ur being the rated voltage), represented by 0, 1, and 2 respectively. It should be noted that the measured voltages for the measurement level and the protection level can be different. For example, the measured voltages for the measurement level can be 0.8Ur, 1.0Ur, and 1.2Ur, while the measured voltages for the protection level can be 0.5Ur, 1.0Ur, and 1.5Ur. Therefore, a test sequence can be represented as a constant consisting of four values.

[0071] Optionally, different control quantities can be represented by different indices. For example, index 3 represents the accuracy class, index 2 represents the winding, index 1 represents the load, and index 0 represents the measured voltage. A test sequence is a string containing four numeric characters, representing, from left to right, the state value corresponding to the accuracy class, the state value of the winding identifier, the state value of the load, and the state value of the measured voltage. Furthermore, the value of the element determined by the values ​​of indices 3 to 0 (the current state of the accuracy class, winding, load, and measured voltage) represents the next state of the accuracy class, winding, load, and measured voltage, i.e., the next test sequence.

[0072] Optionally, the preset test sequence is represented by a 4-dimensional array constant. See details below. Figure 8 The diagram shows a 4D array of constants. Index 3 represents the accuracy level, index 2 represents the winding, index 1 represents the load, and index 0 represents the measured voltage. In step n, the test sequence corresponding to the current state is 0011, which means that the accuracy level is the measurement level, the secondary winding under test with winding identifier 0 is the first secondary winding under test, the load connected to the secondary winding under test with winding identifier 0 is the upper limit load, and the measured voltage is 1.0Ur. Under this condition, the secondary winding under test with winding identifier 0 is tested.

[0073] The next test sequence in step n is 0111, which means that the secondary winding under test with the accuracy class is measurement class and the winding identification is 1 (the first secondary winding under test) is connected to the upper limit load and the measured voltage is 1.0Ur. Under this condition, the secondary winding under test with the winding identification is tested. Figure 8 The experimental order corresponding to steps n+1, n+2, n+3, etc., is also defined in this way, and will not be elaborated here.

[0074] Optionally, the device also includes a current transformer calibrator 9, wherein the voltage output terminal of the winding switching module 4 is connected to the voltage input terminal of the current transformer calibrator 9, and the computer 7 is connected to the current transformer calibrator 9.

[0075] The current transformer calibrator 9 compares the input standard voltage and the voltage being measured, and measures the ratio difference, phase difference, and voltage percentage. The computer 7 reads the measurement result data from the current transformer calibrator 9. The computer 7 automatically reads the measurement results from the current transformer calibrator according to the test procedure and automatically stores them in a data table, thereby realizing automatic storage of measurement data.

[0076] Optionally, the motherboard 3 includes a signal input connector that is connected to the digital output terminal of the data acquisition card.

[0077] Optionally, the voltage load box group 6 mentioned above includes a voltage load box with a number of secondary windings under test.

[0078] Optionally, the computer 7 can send control signals and address signals to the motherboard 3 via the data acquisition card 2, or via other interfaces.

[0079] Optionally, the aforementioned precision transformer module 1 includes a number of precision transformer groups not less than the number of the secondary windings under test. Optionally, the precision transformer module 1 may include 1-5 groups of precision transformers. Since there are usually 5 secondary windings under test, using a number of precision transformer groups not less than the number of the secondary windings under test can ensure that the voltage and current of each secondary winding under test are converted.

[0080] Optionally, each precision transformer group includes a precision voltage transformer and a precision current transformer.

[0081] To better understand the solution of the present invention, the following is in conjunction with... Figures 1 to 7 A more detailed description of the above-mentioned voltage transformer accuracy test and control device is provided.

[0082] In this embodiment, the precision transformer module 1 includes five sets of precision transformers PV1, PA1 to PV5, PA5. Each set of precision transformers includes one precision voltage transformer and one precision current transformer. The voltage transformer under test contains five secondary windings under test, and one set of precision transformers corresponds to one secondary winding under test. See also Figure 3The precision transformer module 1 includes three ports, X1 to X3. The secondary voltage input terminal X1 of the precision transformer module 1 is connected to terminals 1a-5a and 1n-5n of the secondary winding of the voltage transformer under test via five pairs of independent insulated wires. 1a and 1n are terminals corresponding to one secondary winding under test. The voltage of the secondary winding under test of the voltage transformer is converted into a voltage signal representing the voltage of the secondary winding under test by precision voltage transformers PV1-PV5 at a ratio of 150V / 7.07V. Each of the precision voltage transformers PV1-PV5... Each precision voltage transformer has one output terminal connected to the common connection terminal AGND in the voltage signal output terminal X3. The other output terminal of each precision voltage transformer is connected to terminals V1 to V5 in output port X3. Precision voltage transformers PA1 to PA5 convert the voltage signal to a voltage signal representing the measured secondary winding current at a ratio of 5A / 7.07V. Each precision current transformer has one output terminal connected to the common connection terminal AGND in the voltage signal output terminal X3. The other output terminal of each precision current transformer is connected to terminals I1 to I5 in X3. The V1 to V5 terminals of the voltage signal output terminal X3 of precision transformer module 1 are connected to the analog input terminals AI0 to AI4 in data acquisition card 2. The I1 to I5 terminals of X3 are connected to the analog input terminals AI8 to AI12 in data acquisition card 2. The AGND terminal is connected to the analog input terminal AGND in data acquisition card 2.

[0083] The function of the precision transformer module 1 is to convert the voltage and current of the measured secondary winding into a voltage signal acceptable to the data acquisition card 2 in a proportional manner. The essence of the precision transformer module 1 is a transformer, also known as an instrument transformer, which can convert high voltage into low voltage and large current into small current for measurement or protection systems.

[0084] The aforementioned data acquisition card 2 includes a data interface, an analog signal input terminal, and a digital output terminal. The data interface can be a USB interface or a Type-C interface, and it connects to the communication interface of the computer 7. The analog signal input terminal is connected to the signal output terminal of the precision transformer module 1, and the digital output terminal is connected to the motherboard 3. The data acquisition card 2 acquires the voltage signal output by the precision transformer module 1 from the analog signal input terminal to obtain the voltage and current of each measured secondary winding.

[0085] The first function of the data acquisition card 2 is to send the voltage and current of each secondary winding under test to the computer 7 through communication connection. The computer 7 can analyze and process the received voltage and current to obtain the load connected to each secondary winding of the voltage transformer under test and its power factor, so as to realize real-time monitoring and over-limit alarm of the secondary load of the voltage transformer under test.

[0086] The second function of data acquisition card 2 is to receive data sent by computer 7 to control load switching and winding switching, and to convert this data into digital signals and send them to motherboard 3. These digital signals include control signals and address signals for each load switching module and winding switching module.

[0087] See Figure 4 The aforementioned motherboard 3 includes connectors X1 to X8, buffer D1, decoder D2, inverting buffer D3, and linear regulator N1. Connector X8 is connected to the digital output terminal of data acquisition card 2 and buffer D1 and decoder D2 respectively. Decoder D2 is connected to inverting buffer D3. Buffer D1 is connected to connectors X1 to X7. Connectors X1 to X7, buffer D1, decoder D2, and inverting buffer D3 are all connected to linear regulator N1.

[0088] During operation, connector X8 receives control signals from the digital output terminals P0.0 to P0.7 of data acquisition card 2. These signals are buffered by buffer D1 to obtain data signals D0 to D7, which are then connected to connectors X1 to X7 as control signals for load switching and winding switching. Address signals received from the digital output terminals P1.0 to P1.4 of data acquisition card 2 are decoded by decoder D2 and then inverted by inverting buffer D3 to obtain address signals A0 to A7, which are then connected to connectors X1 to X7 as address signals for the load switching module and winding switching module 4. Connectors X1 to X7 are the signal output terminals of motherboard 3. Connectors X1 to X7 can accommodate five load switching modules and one winding switching module 4; any extra modules can be used for functional expansion. Linear regulator N1 converts 12V DC voltage to 5V DC voltage, serving as the operating power for D1 to D3, the load switching module, and the winding switching module 4.

[0089] The first function of the main board 3 is to serve as a motherboard to connect the winding switching module and the five load switching modules. The second function of the main board 3 is to decode the address signals of the winding switching module and the five load switching modules, and after buffering the control signals and the decoded address signals, transmit them to the winding switching module and the five load switching modules through connectors X1 to X7.

[0090] See Figure 5The winding switching module 4 includes a signal input terminal, connector X2, relays K1A to K7A, a data latch D1, and a drive circuit D2. The signal input terminal (connector X1) of the winding switching module 4 is connected to the signal output terminal of the main board 3. Connector X2 includes the input terminals 1a to 4a and da of the secondary winding under test, the input terminals 57.7V and 100V of the standard secondary winding, the standard voltage output terminal Un, and the output terminal Ux of the voltage under test. The winding input terminals are connected to the secondary winding of the voltage transformer under test and the secondary winding of the standard transformer respectively through separate measuring lines. The standard voltage output terminal Un and the output terminal Ux of the voltage under test are connected to the transformer calibrator 9. The function of the winding switching module 4 is to receive the control signal and address signal received at the signal input terminal of the winding switching module 4, latch the control signal using the address signal, control the on / off state of each relay in the winding switching module 4, and connect the selected secondary winding under test and the corresponding secondary winding on the standard transformer to the transformer calibrator 9 through the closed relay contacts. Figure 5 Error measurement is performed using X2 as shown in the figure.

[0091] The specific connection relationship between the winding switching module 4 and other devices is as follows: Connector X1 of the winding switching module 4 is electrically connected to any one of connectors X1 to X7 of the motherboard 3. The signals received by ports D0 to D7 of the winding switching module 4 are connected to the data input terminals D0 to D7 of the data latch D1. A jumper is used to select one of A0 to A7 of connector X1 to connect to the latch input terminal LE of the data latch D1. When the level of the latch input terminal LE changes from low to high, the signals of the data input terminals D0 to D7 of the data latch D1 are latched and output by the data output terminals Q0 to Q7 of the data latch D1. The data output terminals Q0 to Q6 of the data latch D1 drive the coils of relays K1A to K7A through the drive circuit D2, controlling the opening and closing of the contacts of relays K1A to K7A. In this embodiment, A5 can be designated to represent the winding switching module 4, therefore the jumper is connected to A5. One end of the contacts of relays KA1 to KA5 is connected together and then connected to terminal 9 of connector X2, which in turn connects to the Ux input terminal of the current transformer calibrator 9 via connector X2. The other end of the contacts of relays K1A to K5A are connected to terminals 1 to 5 of connector X2, which in turn connects to terminals 1a to 4a and da of the secondary winding under test via connector X2. One end of the contacts of relays KA6 to KA7 is connected together and then connected to terminal 10 of connector X2, which in turn connects to the Un input terminal of the current transformer calibrator 9 via connector X2. The other end of the contacts of relays K6A to K7A are connected to terminals 6 and 7 of connector X2, which in turn connects to the 57.7V and 100V terminals of the standard secondary winding via connector X2.

[0092] See Figure 6The aforementioned load switching module group 5 comprises five load switching modules. Each load switching module includes an output connector X2, a data latch D1, and relays K1A to K7A. The five load switching modules correspond one-to-one with the five tested secondary windings. The input connection terminals a and n of the five load switching modules are respectively connected to the output terminals of the precision transformer module 1. The output connector X2 is connected to the voltage load box group 6. The input connector X1 can be connected to any one of the connectors X1 to X7 on the main board 3. Control signals received through terminals D0 to D7 of the input connector X1 are connected to the data input terminals D0 to D7 of the data latch D1. Address signals A0 to A7 are selected by jumpers and connected to one of A0 to A7 to the latch input terminal LE of the data latch D1. In this embodiment, A0 to A4 are designated as the load switching modules for the tested secondary windings 1a1n to 4a4n and 5a5n, respectively. That is, if the jumper is connected to A0, it indicates that the load switching module is the load switching module for the secondary winding of 1a1n (ports 1a and 1n). Figure 6 As shown in X2), and so on. This allows the control signal transmitted by the data acquisition card 2 to control the on / off state of each relay in the load switching module, thereby controlling the load connected to each tested secondary winding.

[0093] See Figure 7 As shown, the voltage load box 6 can have 5 units, corresponding to the 5 tested secondary windings 1a1n to 4a4n and dadn, respectively. The voltage load box 6 typically has 7 to 8 load units. In this embodiment, there are 7 load units, so the load voltages are 1.25VA, 2.5VA, 5VA, 10VA, 20VA, 40VA, and 80VA, respectively. Each load unit consists of resistors R1, R12, R71, and R72, inductors L1 and L7, and double-pole three-throw toggle switches S1 and S7 connected in series. The toggle switches are used to select a rated voltage of 100V, a rated voltage of 100 / 3V, or to disconnect the load unit. One end of each load unit is connected to the voltage input terminal n, and the other end is led out through connector X1. Voltage input terminals a and n are also led out through connector X1.

[0094] The voltage input terminal of the aforementioned power module 8 is connected to a 220V AC voltage, and the voltage output terminal is connected to the main board 3. This converts the 220V AC voltage into a stable 12V DC voltage, which serves as the operating power for the main board 3, winding switching module 4, and load switching module 5.

[0095] The voltage input terminal of the aforementioned instrument transformer calibrator 9 is connected to the standard voltage and measured voltage output terminals of the winding switching module 4. It compares the output voltage of the secondary winding of the selected measured voltage instrument transformer with the corresponding output voltage of the secondary winding of the selected standard instrument transformer, and measures the ratio error and phase error. The instrument transformer calibrator 9 is equipped with a communication interface; in this embodiment, the communication interface is an RS-232 interface. The computer 7 connects to the instrument transformer calibrator 9 through the communication interface, enabling the instrument transformer calibrator 9 to transmit the measured error and voltage data to the computer 7. The computer 7 automatically stores the received error and voltage data in a data table according to the test procedure.

[0096] In use, the test can be started by setting the rated voltage, lower limit load and upper limit load of each secondary winding under test on the computer 7. The data acquisition card 2 sends the collected voltage and current of the secondary winding under test to the computer 7. The computer 2 calculates the load value and power factor of each secondary winding under test according to its rated voltage, thereby realizing real-time monitoring of the load of the secondary winding under test.

[0097] The aforementioned computer 7 can be a desktop computer or a laptop computer, connected to the data acquisition card 2 via a USB interface, and connected to the current transformer calibrator 9 via a COM1 or USB interface.

[0098] The aforementioned computer 7 is equipped with specially developed measurement and control software. The software interface allows users to set the rated voltage, lower limit load, and upper limit load of each tested secondary winding; to set the model and rated operating voltage of each voltage load box; and to set the test procedure for accuracy testing. It can also display the measured test voltage, power frequency, measured voltage waveform, current waveform, load size, and power factor of each tested secondary winding; and display the connection and disconnection status of the load units in each voltage load box.

[0099] The aforementioned computer 7, under the control of the measurement and control software, receives the voltage and current of the secondary winding under test sent by the data acquisition card 2, and calculates the load size and power factor of each secondary winding under test based on the rated voltage of the secondary winding under test, thereby realizing real-time monitoring of the load of the secondary winding under test. When the measured load size or power factor exceeds the specified limit, an alarm can be triggered.

[0100] The aforementioned computer 7, under the control of the measurement and control software, calculates the on / off state of each load element in the voltage load box 6 according to the set load of each measured secondary winding, the model of the connected voltage load box 6, and the rated working voltage. After encoding the data, it sends it to the data acquisition card 2, which transmits it to the main board 3 through the digital output terminal of the data acquisition card 2. The main board 3 transmits it to the data port and address port of the winding switching module 4 and the load switching module group 5. Each load switching module in the winding switching module 4 and the load switching module group 5 latches its own control signal, which is then driven by the drive circuit to drive the relay coil to control the on / off state of each load unit in the voltage load box 6, thereby realizing the automatic switching of each measured secondary winding and its load.

[0101] The aforementioned computer 7, under the control of the measurement and control software, receives the measurement result data sent by the current transformer calibrator 9 and automatically stores it in the database or test record file.

[0102] Under the control of the measurement and control software, the computer 7 automatically switches the tested secondary winding, automatically switches the light load and full load connected to the tested secondary winding, automatically switches the standard secondary winding, and automatically collects and displays the measurement result data of the current transformer calibrator 9 and stores it in the database or test record file according to the preset test procedure. During the entire test process, the test personnel only need to click the data confirmation button after the measurement result data of the current transformer calibrator 9 stabilizes, except for operating the raising and lowering of the test power supply.

[0103] In summary, the solution of this invention allows for sequential control according to a preset test procedure. At each test step, the voltage, current load, and power factor of each secondary winding of the voltage transformer under test can be monitored in real time. The secondary winding of the voltage transformer under test can be automatically switched, as can the secondary winding of the standard voltage transformer. Load switching is automatically performed according to the lower limit load switching and upper limit load setting values. The measurement result data of the transformer calibrator 9 is automatically collected, displayed, and stored in the test record file, simplifying the operation process for test personnel and improving testing efficiency.

[0104] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the description above. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, using the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A voltage transformer accuracy test measurement and control device, characterized in that: The precision transformer module, the data acquisition card, the mainboard, the winding switching module, the load switching module group and the computer, the load switching module group includes a plurality of load switching modules, one load switching module corresponds to a measured secondary winding; The winding input end of the precision transformer module is connected with a plurality of measured secondary windings of the measured voltage transformer, the winding output end of the precision transformer module is connected with the load switching module group, and the signal output end of the precision transformer module is connected with the data acquisition card; the data acquisition card is connected with the computer and the mainboard respectively; the signal output end of the mainboard is connected with the winding switching module and the load switching module group respectively, and the winding input end of the winding switching module is connected with a plurality of standard secondary windings and a plurality of measured secondary windings of the standard voltage transformer respectively; The precision transformer module is used for converting the voltage and current of each measured secondary winding according to the set ratio and sending the converted voltage and current signals to the data acquisition card. The computer is used for collecting the voltage and current signals of each measured secondary winding through the data acquisition card and monitoring the load value connected to each measured secondary winding in real time. The computer is also used for determining a target measured secondary winding, a target standard secondary winding and a target load value corresponding to the target measured secondary winding according to a preset test process, generating a winding switching module corresponding to the target measured secondary winding and a control signal and an address signal corresponding to each module of the load switching module, and sending the generated control signal and address signal to the mainboard; for each winding switching module, the address signal represents the corresponding identification of the winding switching module; for each load switching module, the address signal represents the corresponding identification of the load switching module; for each load switching module and winding switching module, the control signal includes the current target load value of the load switching module, the identification of the current target measured secondary winding and the identification of the current target standard secondary winding; The mainboard is used for controlling the on-off of each relay in the winding switching module according to the identification of the current target measured secondary winding and the identification of the current target standard secondary winding, so as to determine the current target measured secondary winding and the current target standard secondary winding; and controlling the load value connected to the target measured secondary winding through the load switching module corresponding to the address signal according to the address signal, so that the load value connected to the current target measured secondary winding is the current target load value.

2. The voltage transformer accuracy test measurement and control device according to claim 1, characterized in that: The voltage load box group includes not less than the number of voltage load boxes corresponding to the measured secondary windings, and each load unit in each voltage load box is led out through a connector to control the load corresponding to the corresponding voltage load box through the connector.

3. The voltage transformer accuracy test measurement and control device according to claim 1, characterized in that: The precision transformer module includes not less than the number of precision transformer groups corresponding to the measured secondary windings.

4. The voltage transformer accuracy test control device according to claim 3, characterized in that, Each precision transformer group includes a precision voltage transformer and a precision current transformer.

5. The voltage transformer accuracy test measurement and control device according to any one of claims 1 to 4, characterized in that: The mainboard comprises a signal input connector connected with a digital output end of the data acquisition card.

6. The voltage transformer accuracy test measurement and control device according to any one of claims 1 to 4, characterized in that: The transformer calibrator is further connected with the voltage output end of the winding switching module and the computer.

7. The voltage transformer accuracy test measurement and control device according to any one of claims 1 to 4, characterized in that: The computer is further configured to analyze and process the voltage and current signals collected by the data acquisition card, calculate and display the load and power factor of each measured secondary winding connected with the load.

8. The voltage transformer accuracy test measurement and control device according to claim 2, characterized in that: The computer is further configured to convert the preset target load value into a 7-bit binary control signal according to a preset encoding method.

9. The voltage transformer accuracy test measurement and control device according to any one of claims 1 to 4, characterized in that: The preset test procedure comprises a preset test sequence, and the preset test sequence comprises a plurality of test sequences each composed of a state value corresponding to each of a plurality of control quantities, wherein the plurality of control quantities comprise an accuracy level, a winding identifier of a measured secondary winding, a load value and a measurement voltage, the state value corresponding to the accuracy level comprises a state value corresponding to a measurement level and a state value corresponding to a protection level, the winding identifier comprises a plurality of winding identifiers each corresponding to a state value, the load value comprises a plurality of load values each corresponding to a state value, and the measurement voltage comprises a plurality of measurement voltages each corresponding to a state value, and each test sequence comprises one state value corresponding to each of the control quantities. When determining a target measured secondary winding, a target standard secondary winding and a target load value corresponding to the target measured secondary winding according to a preset test procedure, the computer is specifically configured to: determine the target measured secondary winding, the target standard secondary winding and the target load value corresponding to the target measured secondary winding according to the preset test sequence.

10. The voltage transformer accuracy test measurement and control device according to claim 9, characterized in that: The preset test sequence is represented by a 4-dimensional array constant.

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