CN109407036B - A fully automatic calibration device for batch current transformers based on PLC control - Google Patents

Abstract

The invention discloses a full-automatic transformer calibrating device based on PLC control, which has the advantages that after PLC is added to control, compared with a singlechip control circuit, the full-automatic transformer calibrating device is stable and reliable, has strong anti-interference capability, greatly reduces the fault maintenance rate and has high degree of automation; in addition, a method for opening and testing the primary series up-flow secondary terminal parallel synchronous detection stations of the tested current transformer is adopted, even if the current transformers are connected in parallel in batches, the impedance of an external lead of a secondary loop of the current transformer can be accurately controlled to meet the regulation requirement of 0.05 omega or 0.06 omega, the accuracy of verification errors is ensured, the current transformer is prevented from being damaged by secondary open circuit by adopting a technical method of switching stations in a mode of delaying 5-10 milliseconds after the first connection and the last disconnection through PLC programming control, so that the full-automatic verification of larger batches of through-core current transformers can be realized, the pipeline detection can be realized by adding electromechanical control equipment by the method, and the detection working efficiency is greatly improved; the device is used for calibrating the non-through type current transformer and the voltage transformer automatically.

Description

A fully automatic calibration device for batch current transformers based on PLC control

Technical field

The invention relates to the technical field of transformer detection, specifically a fully automatic calibration device for batch feed-through current transformers based on PLC industrial control.

Background technique

The transformer calibration device is a special precision instrument that is used to calibrate and test the error of the transformer before installation in order to ensure the accuracy of the transformer in the power metering device of the power system. Currently, there are many forms of transformer calibration devices commonly used in power systems. Among them, the more advanced fully automatic transformer calibration and verification device has measuring points that can automatically perform full load and light load measurements according to the current or voltage requirements of different transformation ratios according to the requirements of the transformer calibration regulations. The instrument transformer calibration management software automatically consolidates the error data of the test data according to the accuracy level of the tested instrument transformer, and determines whether it is out of tolerance. The load gear of the transformer load box switches automatically without manual switching. The device can also automatically complete the closed-circuit demagnetization test of the transformer and has a variety of protection functions. However, because they are all controlled by single-chip computers, their stability and reliability are poor, and their maintenance rates are high, making it inconvenient for users to program, modify and maintain as needed. Since the calibrated current transformers are all serially connected in batches, the cumulative relay contact resistance exceeds the secondary impedance requirements stipulated in the regulations. The batch size of one installation is usually limited to no more than 12 current transformers. Otherwise, the secondary load deviation will seriously affect the error of the detected transformer and cause inaccurate electric energy measurement. As the demand for transformers increases due to power grid upgrades and transformations, the amount of testing of transformers increases simultaneously. There is a great need to improve the efficiency of transformer detection and reduce operation and maintenance costs. This reflects the parallel connection based on PLC industrial control. The secondary terminal and accurate control of the secondary impedance can realize the advantages of the device for fully automatic verification of large batches of feedthrough current transformers.

Contents of the invention

The purpose of the present invention is to provide a device based on PLC control that connects secondary terminals in parallel and accurately controls the secondary impedance, which can realize fully automatic verification of large batches of feedthrough current transformers, and can also verify non-feedthrough current transformers. transformers and voltage transformers to solve the problems raised in the above background technology.

In order to achieve the above object, the present invention provides the following technical solution: a fully automatic calibration device for batch current transformers based on PLC control. The device is equipped with a host computer, one end of the host computer is connected to the transformer calibrator, and the host computer The other end is connected to the programmable controller. It is also possible that the host computer is only connected to the programmable controller, and the programmable controller is then connected to the transformer calibrator. The device is also equipped with a current transformer load box, a voltage transformer load box, and a voltage regulating output bus. form, AC contactor, etc. One side of the AC contactor is equipped with a digital current/voltage meter, a standard current transformer secondary tap group, a self-boosting standard current transformer, a self-boosting standard voltage transformer, and auxiliary tests. Station N station group; the current transformer load box and voltage transformer load box may also be a combined current and voltage transformer load box; the voltage regulating output assembly is composed of a coarse-adjusting electric voltage regulator assembly, The fine-tuning electric voltage regulator assembly is connected to each other through an intermediate transformer wire package and may be replaced by a program-controlled electronic source; the standard current transformer secondary tap group and the self-rising standard current transformer may also be with a transformation ratio of two The self-boosting smart standard current transformer of the secondary tap conversion relay may also be used separately from the current transformer and the standard current transformer and the standard current transformer secondary tap group; the self-boosting standard current transformer may also be a rising current transformer. The voltage transformer and the standard voltage transformer are used separately; the program-controlled instrument is composed of a PLC programmable controller and its programmable control touch screen and acquisition circuit; one end of the N station group of the auxiliary test bench is connected to the transformer calibrator Connect one end.

Preferably, the N station group of the auxiliary test bench is equipped with N (1 ≤ N < 100) automatic switching of stations, and the programmable controller controls the automatic switching of N stations on the auxiliary bench and the self-rising standard current transformer. Automatic switching of multi-ratio secondary taps, automatic switching of load gears between current transformer load box and voltage transformer load box, automatic rise and fall of voltage regulator output assembly, and AC contactor pull-in, programmable controller and transformer The calibrator related signal collection, the digital ammeter is connected in series to the secondary current loop of the transformer calibrator, the digital voltmeter is integrated into the secondary voltage loop of the transformer calibrator, the programmable controller is connected to the digital current/voltage meter, and the programmable controller controls the mutual inductance The automatic or manual operating status of the calibrator.

Preferably, the N feed-through current transformers on the auxiliary table of the programmable controller control device each have one turn through the core at a time, and the secondary terminals are connected in parallel and connected to the workstation group according to the polarity markings.

Compared with the prior art, the beneficial effects of the present invention are:

After the PLC of the present invention is added to the control, the control circuit is more stable and reliable than the single-chip microcomputer, and has strong anti-interference ability, which greatly reduces the fault repair rate and has a high degree of automation. In addition, the tested current transformer is used to connect the primary series upcurrent secondary terminals in parallel for synchronous detection. With the bit open test method, even if current transformers are connected in parallel in batches, the external wire resistance of the current transformer's secondary circuit can be accurately controlled to make it meet the regulatory requirements of 0.05Ω or 0.06Ω, ensuring the accuracy of the calibration error, and controlling the first connection through PLC programming The technical method of switching stations with a post-break delay of 5 to 10 milliseconds ensures that there is no worry of secondary open circuits. This can realize fully automatic verification of larger batches of through-core current transformers. This method can also be used to add electromechanical control equipment to realize assembly line inspection. , greatly improving the detection efficiency; the device automatically performs single-unit verification on non-through-core current transformers and voltage transformers.

Description of drawings

Figure 1 is a schematic block diagram of the device configuration of the present invention based on PLC control of parallel connection of secondary terminals and accurate control of secondary impedance to achieve fully automatic verification of batch feed-through current transformers;

Figure 2 is a three-dimensional schematic view of the auxiliary table of the present invention;

Figure 3 is a schematic wiring diagram of the detection and control principle of the current transformer of the present invention;

Figure 4 is a schematic wiring diagram of the detection and control principle of the voltage transformer of the present invention;

Figure 5 is a schematic diagram of the second configuration of the device according to the present invention, which can realize fully automatic verification of batch feed-through current transformers by accurately controlling the secondary impedance by connecting secondary terminals in parallel under PLC control;

Figure 6 is a schematic wiring diagram of the detection and control principle of the second configuration of the current transformer of the present invention;

Figure 7 is a schematic wiring diagram of the detection and control principle of the voltage transformer with the second configuration of the present invention;

In the picture: 1. A device based on PLC-controlled parallel connection of secondary terminals to accurately control the secondary impedance to realize fully automatic calibration of batch current transformers; 2. Host computer; 3. Transformer calibrator; 4. Programmable controller; 5. Current transformer load box; 6. Digital current/voltage meter; 7. AC contactor; 8. Voltage regulating output assembly; 9. Self-rising standard current transformer; 10. Auxiliary station N station group; 11 , tested current transformer; 12. tested voltage transformer; 13. self-boosting standard voltage transformer; 14. voltage transformer load box; 15. standard current transformer secondary tap group.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

Embodiment 1: Please refer to Figures 1, 2, 3, and 4. The present invention provides a technical solution: a fully automatic verification device for batch current transformers based on PLC control. The overall structure of the device 1 is controlled by a computer. It consists of a main console, a main console and an auxiliary console. A host computer 2 including transformer calibration management system software is installed on the computer console, which communicates bidirectionally with the PLC in the transformer calibrator 3 and program controller 4 in the main console through the RS232 interface. ; The main console is equipped with a transformer calibrator 3, a program controller 4, a current transformer load box 5, a digital current/voltage meter 6, an AC contactor 7, and a voltage regulating output assembly 8; the auxiliary console is configured as shown in Figure 2. Up-current standard current transformer 9, auxiliary station N station group 10, self-boosting standard voltage transformer 13 (high voltage safety distance requirements of safety regulations are generally placed separately next to the auxiliary station), voltage transformer load box 14, standard The current transformer secondary tap group 15; the digital current/voltage meter 6 communicates with the PLC in the program controller 4 through the RS485 interface to provide current/voltage digital signals. The PLC in the program controller (4) is also connected to control the transformer calibrator 3 and Current transformer load box 5, AC contactor 7, voltage regulating output assembly 8, self-rising standard current transformer 9, auxiliary station N station group 10, voltage transformer load box 14, standard current transformer secondary tap Group 15, T ₀ of the transformer calibrator 3 is connected to the standard current transformer secondary tap group 15 through the ammeter of the series digital current/voltage meter 6 and then to the secondary non-polar terminal K _X of the self-rising standard current transformer 9 Connection, _T The contacts are connected in parallel to connect the secondary non-polar terminals S2 of the N tested current transformers 11, and the K _i of the transformer calibrator 3 are connected to the secondary polar terminal K1 of the self-rising standard current transformer 9 and then connected in parallel. The secondary polarity terminals S1 of the N tested current transformers 11 and D of the transformer calibrator 3 are connected to the ground terminal of the instrument and then grounded. The voltage regulating output assembly 8 is connected to the contact selection switch of the AC contactor 7 and connected to the automatic The primary circuit of the current riser in the self-rise standard current transformer 9, the current riser in the self-rise standard current transformer 9 simultaneously connects the standard current transformer in the self-rise standard current transformer 9 and N test currents. The transformer 11 is connected in series to form a closed loop through the primary polarity end-to-top method, thus forming the detection and control circuit of the current transformer; in addition, the a and x terminals of the transformer calibrator 3 are connected in parallel through the digital current/voltage meter 6 The voltmeter is connected correspondingly to the self-boosting standard voltage transformer 13. The polarity terminal a of the self-boosting standard voltage transformer 13 is connected to the polarity terminal a of the tested voltage transformer 12, and K _U of the transformer calibrator 3. Connect the secondary non-polar terminal x of the voltage transformer under test 12 and D of the transformer calibrator 3 to the secondary non-polar terminal x of the voltage transformer under test 12. At the same time, connect the ground terminal of the instrument and then ground it to adjust the voltage output. The contact selection switch of the assembly 8 is connected to the AC contactor 7 and is connected to the primary circuit of the booster in the self-boosting standard voltage transformer 13. The booster in the self-boosting standard voltage transformer 13 simultaneously connects the self-boosting standard The standard voltage transformer in the voltage transformer 13 and the tested voltage transformer 12 are connected in parallel to form a closed loop by connecting the primary polarity terminals to each other and the non-polar terminals to each other and grounding. This forms the detection and control of the voltage transformer. line.

Current transformer detection process: The programmable controller 4 includes a PLC programmable controller and its programmed-controlled touch screen and acquisition circuit. The programmable controller 4 receives the operating instructions of the host computer 2 and simultaneously transmits back the data information and digital current/voltage of the host computer 2. The ammeter in Table 6 and the transformer calibrator 3 synchronously receive the rated secondary current signal from the standard transformer in the self-rising standard current transformer 9, convert it into a digital signal, and then communicate with the PLC in the program controller 4 through the RS485 interface. Programmable control The PLC in the instrument 4 receives signals in real time and controls the manual or automatic state of the transformer calibrator 3, the load switching of the current transformer load box 5, the contact opening and closing of the AC contactor 7, and the voltage regulation output through the programmed instructions. The output voltage of the assembly 8 is adjusted so that the current riser of the self-rising standard current transformer 9 is connected in series with the primary currents of N tested current transformers 11 to rise and fall, and the secondary sides and standard currents of all current transformers are synchronously induced electromagnetically. The transformation ratio of the transformer secondary tap group 15 is converted so that the standard current transformer of the self-rising standard current transformer 9 has the same transformation ratio as the N tested current transformers 11, and the N station group 10 of the auxiliary station is connected in parallel with N tested current transformers. The test station of current transformer 11 is first connected and then disconnected, and the through-core current transformers are switched sequentially one by one to facilitate error test points. The secondary side of the standard and tested current transformer passes through the primary side at each procedure test point. The electromagnetic induced current and differential current are synchronized point by point and sent to the transformer calibrator 3 for calculation and processing. The transformer calibrator 3 converts the received analog signal through A/D and synchronizes the data processed by the microprocessor. It is sent back to the host computer 2 for judgment and further processing, thereby achieving the purpose of batch verification of through-core current transformers.

Embodiment 2: Please refer to Figure 5, Figure 2, Figure 6, and Figure 7. The present invention provides another technical solution: a fully automatic verification device for batch current transformers based on PLC control. The overall structure of the device 1 is composed of It consists of a computer station, a main console and an auxiliary station. The computer station is equipped with a host computer 2 including transformer calibration management system software. The host computer 2 communicates with the PLC in the mileage controller 4 of the main console through the RS232 interface; the main console Installed are transformer calibrator 3, program controller 4, current transformer load box 5, voltage transformer load box 14, AC contactor 7, voltage regulating output assembly 8; the auxiliary station is configured with self-rising standard current as shown in Figure 2. Transformer 9, auxiliary station N station group 10, self-boosting standard voltage transformer 13 (high voltage safety distance requirements of safety regulations are generally placed separately next to the auxiliary station), standard current transformer secondary tap group 15; programmable control instrument The PLC in 4 communicates bidirectionally with the transformer calibrator 3 through the RS232 interface, and is also connected to the control current transformer load box 5, AC contactor 7, voltage regulating output assembly 8, self-rising standard current transformer 9, and auxiliary station N station group 10, voltage transformer load box 14, standard current transformer secondary tap group 15, T ₀ of transformer calibrator 3 is connected to the standard current transformer secondary tap group 15 and then with the self-rising standard current _The secondary non-polar terminal _K The polarity end station relay corresponds to N normally open contacts and is connected in parallel to connect the secondary non-polar ends S2 of N tested current transformers 11 and K _i of the transformer calibrator 3 to connect the self-rising standard current transformer. The secondary polarity terminal K1 of the instrument 9 is then connected in parallel to the secondary polarity terminal S1 of N tested current transformers 11 and D of the transformer calibrator 3 to the instrument grounding terminal and then to ground, and the voltage regulating output assembly 8 is connected to the AC contact The contact selection switch of the self-rising standard current transformer 9 is connected to the primary circuit of the current riser in the self-rise standard current transformer 9. The current riser in the self-rise standard current transformer 9 simultaneously connects the current riser in the self-rise standard current transformer 9. The standard current transformer and N tested current transformers 11 are connected in series to form a closed loop through the primary polarity end-to-top method, thus forming the detection and control circuit of the current transformer; in addition, a and x of the transformer calibrator 3 The terminals are connected correspondingly to the self-boosting standard voltage transformer 13, the polarity terminal a of the self-boosting standard voltage transformer 13 is connected to the polarity terminal a of the tested voltage transformer 12, and the K _U connection of the transformer calibrator 3 The secondary non-polar terminal x of the voltage transformer under test 12 and D of the transformer calibrator 3 are connected to the secondary non-polar terminal x of the voltage transformer under test 12. At the same time, they are connected to the ground terminal of the instrument and then grounded. The total voltage regulation output The contact selection switch of the AC contactor 7 is connected to the primary circuit of the booster in the self-boosting standard voltage transformer 13. The booster in the self-boosting standard voltage transformer 13 simultaneously switches the self-boosting standard voltage The standard voltage transformer in the transformer 13 and the tested voltage transformer 12 are connected in parallel to form a closed loop by connecting the primary polarity terminals to each other and the non-polar terminals to each other and grounding. This forms the detection and control circuit of the voltage transformer. .

Current transformer detection process: The programmable controller 4 includes a PLC programmable controller and its programmed-controlled touch screen and acquisition circuit. The programmable controller 4 receives the operating instructions of the host computer 2 and transmits back the data information of the host computer 2 at the same time. The programmable controller 4 communicates with The transformer calibrator 3 controls and receives the error calculation data of the transformer calibrator 3 through RS232 two-way communication. The PLC in the programmable controller 4 receives the signal of the transformer calibrator 3 in real time and controls the transformers respectively through programmed instructions. The manual or automatic state of the calibrator 3, the load switching of the current transformer load box 5, the contact opening and closing of the AC contactor 7, and the adjustment of the output voltage of the voltage regulating output assembly 8 make the self-rising standard current transformer The current riser of 9 is connected in series with the primary current rise and fall of N tested current transformers 11 and synchronizes the electromagnetic induction to the secondary side of all current transformers and the transformation ratio conversion of the standard current transformer secondary tap group 15, thereby making the self-rise current standard The standard current transformer of the current transformer 9 has the same transformation ratio as the N tested current transformers 11. The N station group 10 of the auxiliary station is connected in parallel. The stations of the N tested current transformers 11 are connected first and then disconnected one by one with delay. Switching, the current and differential current induced by the electromagnetic induction of the primary side at each regulation test point on the secondary side of the standard and tested current transformer are synchronously transmitted point by point to the transformer calibrator 3, and the transformer calibrator 3 The received analog signal is A/D converted and the data processed by the microprocessor is synchronously transmitted to the host computer 2 for judgment and further processing through the programmable controller 4, thereby achieving the purpose of batch verification of through-core current transformers.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art will understand that various changes, modifications, and substitutions can be made to these embodiments without departing from the principles and spirit of the invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (4)

1. Full-automatic calibrating installation of batch current transformer based on PLC control, its characterized in that: the device (1) is composed of a computer table, a main control table and an auxiliary table in the overall structure, wherein an upper computer (2) comprising transformer verification management system software is arranged on the computer table and is respectively in bidirectional communication with a transformer calibrator (3) in the main control table and a PLC (programmable logic controller) in a program control instrument (4) through an RS232 interface; the main control desk is provided with a transformer calibrator (3), a program control instrument (4), a current transformer load box (5), a digital current/voltage meter (6), an alternating current contactor (7) and a voltage regulation output assembly (8); the auxiliary platform is provided with a self-lifting standard current transformer (9), an auxiliary platform N-working group (10), a self-lifting standard voltage transformer (13), a voltage transformer load box (14) and a standard current transformer secondary tap group (15); the digital current/voltage meter (6) is communicated with a PLC in the program control instrument (4) through an RS485 interface, the PLC in the program control instrument (4) is also respectively connected with and controls a transformer calibrator (3), a current transformer load box (5), an alternating current contactor (7), a voltage regulating output assembly (8), a self-elevating standard current transformer (9), an auxiliary station N working bit group (10), a voltage transformer load box (14), a standard current transformer secondary tap group (15) and a T of the transformer calibrator (3) ₀ The secondary tap group (15) of the standard current transformer is connected with the secondary nonpolar end K of the self-elevating standard current transformer (9) through an ammeter connected with the digital current/voltage meter (6) in series _X T of connecting and mutual inductor calibrator (3) _X The secondary nonpolar end S2 of the N tested current transformers (11) are connected in parallel with N normally open contacts corresponding to N nonpolar end station relays of the N tested current transformers (11) of the auxiliary station N station group (10) through being connected in series with the current transformer load box (5) and then being connected with the transformer calibrator(3) K of (2) _i The secondary polarity end S1 of N tested current transformers (11) are connected in parallel with the secondary polarity end K1 of the self-elevating standard current transformer (9), the grounding terminal of a D connecting instrument of the transformer calibrator (3) is grounded, the voltage regulating output assembly (8) is connected with a contact selection switch of an alternating current contactor (7) to be connected into a primary loop of the current riser in the self-elevating standard current transformer (9), the current riser in the self-elevating standard current transformer (9) simultaneously connects the standard current transformers in the self-elevating standard current transformer (9) and the N tested current transformers (11) in series into a closed loop in a primary polarity end-to-top mode, so that a detection and control circuit of the current transformers is formed, the station first-to-break delay of the N tested current transformers (11) is connected in parallel with the auxiliary station N station group (10) and is switched in one station first-to-station first-to-break delay, and the station first-to-break switching is controlled by a PLC (4) to control delay for 5-10 milliseconds, and the station first-to break switching is controlled by the PLC to ensure that the current transformer has no secondary open circuit.

2. The full-automatic verification device for batch current transformers based on PLC control according to claim 1, wherein the full-automatic verification device is characterized in that: the programmable controller (4) comprises a Programmable Logic Controller (PLC) and a touch screen and an acquisition circuit which are controlled by the PLC, the programmable controller (4) receives an operation instruction of the upper computer (2), the ammeter of the digital ammeter/voltmeter (6) and the transformer calibrator (3) synchronously receive rated secondary current signals of the standard transformer from the current-up standard transformer (9) and convert the rated secondary current signals into digital signals, and then communicate with the PLC in the programmable controller (4) through an RS485 interface, the PLC in the program control instrument (4) receives the signal in real time and controls the manual or automatic state of the transformer calibrator (3), the load switching of the current transformer load box (5), the contact on-off of the alternating current contactor (7) and the height adjustment of the output voltage of the voltage regulating output assembly (8) respectively through the programmed instruction, so that the primary current of the N tested current transformers (11) in series connection with the current rising of the self-rising standard current transformers (9) is lifted and synchronously and electromagnetically inducted to the secondary sides of all the current transformers, the transformation ratio of the standard current transformer secondary tap group (15) is converted, so that the transformation ratio of the standard current transformers of the self-rising standard current transformers (9) is consistent with that of the N tested current transformers (11), the station make-up time delay one-by-one through-core type current transformer sequential switching of N tested current transformers (11) in parallel connection with the auxiliary station N work bit group (10) is convenient for error test sampling points, the current and differential current of the standard and tested current transformers, which are obtained by electromagnetic induction of the primary side at the secondary side of each rule test point, are transmitted to the transformer calibrator (3) in a point-by-point synchronous and sequential mode for operation processing, and the transformer calibrator (3) synchronously transmits the data of the received analog signals, which are subjected to the operation processing of the microprocessor through A/D conversion, to the upper computer (2) for judgment and reprocessing, so that the aim of batch verification of the through current transformers is fulfilled.

3. Full-automatic calibrating installation of batch current transformer based on PLC control, its characterized in that: the device (1) is composed of a computer table, a main control table and an auxiliary table in the overall structure, wherein an upper computer (2) comprising transformer verification management system software is installed on the computer table, and the upper computer (2) and a PLC (programmable logic controller) in a main control table mileage controller (4) are in bidirectional communication through an RS232 interface; the main control desk is provided with a transformer calibrator (3), a program control instrument (4), a current transformer load box (5), an alternating current contactor (7) and a voltage regulation output assembly (8); the auxiliary platform is provided with a self-lifting standard current transformer (9), an auxiliary platform N-working group (10), a self-lifting standard voltage transformer (13), a voltage transformer load box (14) and a standard current transformer secondary tap group (15); the PLC in the program control instrument (4) is in bidirectional communication with the transformer calibrator (3) through an RS232 interface, and is also respectively connected with and controls a current transformer load box (5), an alternating current contactor (7), a voltage regulating output assembly (8), a self-lifting standard current transformer (9), an auxiliary station N working bit group (10), a voltage transformer load box (14) and a standard current transformer secondary tap group (15), and the T of the transformer calibrator (3) ₀ The secondary tap group (15) of the standard current transformer is connected with the secondary nonpolar end K of the self-elevating standard current transformer (9) _X T of connecting and mutual inductor calibrator (3) _X The secondary nonpolar end S2 of the N tested current transformers (11) and the K of the transformer calibrator (3) are connected in parallel with N normally open contacts corresponding to N tested current transformer (11) nonpolar end station relays of the N working groups (10) of the auxiliary station in series with the current transformer load box (5) to be butted _i The secondary polarity end K1 of the self-current-rising standard current transformer (9) is connected in parallel with NThe secondary polarity end S1 of each tested current transformer (11) and the grounding terminal of the D connecting instrument of the transformer calibrator (3) are grounded, the voltage regulating output assembly (8) is connected with a contact selection switch of the alternating current contactor (7) to be connected into a primary loop of a current booster in the self-boosting standard current transformer (9), the current booster in the self-boosting standard current transformer (9) simultaneously connects the standard current transformers in the self-boosting standard current transformer (9) and N tested current transformers (11) in series into a closed loop in a primary polarity end-to-end manner, thus a detection and control circuit of the current transformers is formed, and stations of the N station groups (10) of the auxiliary stations connected with the N tested current transformers (11) in parallel are connected in a first-break and last-delay sequential switching mode one by one.

4. The full-automatic verification device for batch current transformers based on PLC control according to claim 3, wherein: the programmable logic controller (4) comprises a Programmable Logic Controller (PLC) and a touch screen and an acquisition circuit which are controlled by programming the programmable logic controller, the programmable logic controller (4) receives an operation instruction of the upper computer (2) and simultaneously returns data information of the upper computer (2), the programmable logic controller (4) and the transformer calibrator (3) are controlled through RS232 bidirectional communication and receive error operation data of the transformer calibrator (3), the PLC in the programmable logic controller (4) receives signals of the transformer calibrator (3) in real time and respectively controls the manual or automatic state of the transformer calibrator (3) through programmed instructions, the load of a current transformer load box (5) is switched, the contacts of an alternating current contactor (7) are switched on and off, the voltage regulating output assembly (8) is regulated in output voltage, so that primary current of N tested current transformers (11) are connected in series with an up-converter of the up-converter standard current transformer (9) and synchronous electromagnetic induction is conducted to the secondary side of all the current transformers, the transformation ratio conversion of a secondary tap group (15) of the standard current transformer is conducted on the up-converter (9) and the secondary side of the current transformer is conducted to the secondary side of the current transformer through the up-converter, and the standard transformer is conducted on the secondary side of the current transformer (11) and the secondary current transformer in parallel to the up converter of the up converter standard current transformer (9) through the standard current transformer, the transformer calibrator (3) synchronously transmits the data which is processed by the microprocessor operation and is subjected to the A/D conversion to the upper computer (2) through the program control instrument (4) for judgment and reprocessing, thereby realizing the purpose of batch verification of the through type current transformer.