CN105334375A - PT-CT combined device capable of being installed in charged mode - Google Patents

Abstract

The invention discloses a PT and CT combination device capable of live installation, which includes a phase A detection unit, a B phase detection unit, a C phase detection unit, a control module, a wireless communication module and a low-voltage side power supply module, the A phase The detection unit, phase B detection unit and phase C detection unit all include high voltage equipotential open current transformer, high voltage equipotential current sampling module, capacitive energy transformer, high voltage equipotential voltage energy harvesting power supply module, electronic voltage transformer And voltage signal sampling module. The invention can collect high-voltage electric power under the condition of uninterrupted power supply and will not cause hidden danger to the safe operation of the power grid when it is installed and used in a large area.

Description

PT, CT combination device that can be installed live

technical field

The invention relates to a voltage and current detection device of a power supply line, in particular to a PT and CT combination device capable of live installation.

Background technique

With the development and implementation of smart grid technology, it is often necessary to extract current and voltage signals of different occasions from the power system and transmit them to the corresponding application system to provide information for power quality monitoring and improvement, distribution network automation, and power grid information transparency. The application provides a reliable signal source, so that the corresponding application system can fully play its role.

To improve the power quality of the power grid, it is first necessary to accurately detect and analyze the voltage and current through appropriate detection components, measure the power quality level of the power grid, and analyze and judge the causes of various power quality problems. Provide a basis for the improvement of power quality. As the power supply network of the final power users, the 10kV distribution network has the most extensive divisions, the most complex network structure and load changes, and its power quality is most susceptible to being affected because it is directly connected to the power supply load. From the perspective of the entire grid system, improving the power quality level of the distribution network has made a significant contribution to improving the power quality level of the entire grid; from the perspective of the power supply function of the distribution network, it is increasingly necessary to directly monitor the power quality from the high-voltage side. Effectively optimize and improve the power quality of the 10kV distribution network, which directly determines the power quality of the upstream power grid and downstream users. However, as users have higher and higher requirements for power supply reliability, power outage construction is becoming more and more difficult, and most online monitoring of power quality needs to be installed live in the existing operating grid, but high-voltage traditional electromagnetic transformers cannot Live installation under the condition of continuous line and power failure, and due to the principle defects such as easy magnetic saturation, narrow measurement range and response frequency band, easy ferromagnetic resonance, large power consumption, etc., and a large number of installations will increase the ferromagnetic resonance point of the line, Defects such as increasing line reactive power and reducing the level of safe and economical operation of the grid make existing equipment unable to meet the needs of grid users for fast and flexible distributed networking to obtain big data.

Publication number: 201310500019.8, titled: Invention patent of voltage transformer, discloses a voltage transformer, including epoxy resin mixed adhesive layer, primary winding, secondary winding, iron core, the iron core of the transformer is cold Rolled grain-oriented silicon steel strip is coiled to form a hollow cylindrical iron core with a circular cross-section. A secondary winding is wound on the iron core, and a primary winding is wound on the outside of the secondary winding, wrapped with an epoxy resin mixed adhesive layer. It is located on the outer circumference of the main body of the transformer composed of primary winding, secondary winding and iron core. The core material of the transformer adopts computer design and cutting technology. It is made of cold-rolled grain-oriented silicon steel strip with high magnetic flux density and low iron loss. There is no air gap in the center, and the magnetostrictive force is easily absorbed. After the iron core is treated by strict annealing process, the magnetic permeability of the material can be fully restored. Small magnetic flux leakage, low loss, low temperature rise, low noise, and dynamic performance of withstand overload Good advantages, but the voltage transformer cannot collect high-voltage electricity in the case of uninterrupted power supply, and it is easy to affect the safe operation of the power grid when installed in a large area.

Contents of the invention

In view of this, the purpose of the present invention is to address the deficiencies of the prior art, to provide a PT and CT combination device that can be installed live, which solves the problem that the prior art cannot collect high-voltage electricity and install it in a large area under the condition of continuous power failure. The grid security operation problems caused by it.

To achieve the above object, the present invention adopts the following technical solutions:

A PT and CT combination device capable of live installation, including a phase A detection unit, a B phase detection unit, a C phase detection unit, a control module, a wireless communication module and a low voltage side power supply module, the A phase detection unit, B phase detection unit Both the phase detection unit and the C-phase detection unit include a high-voltage equipotential open current transformer, a high-voltage equipotential current sampling module, a capacitive energy transformer, a high-voltage equipotential voltage energy harvesting power supply module, an electronic voltage transformer and a voltage signal sampling module, the high-voltage equipotential current sampling module is electrically connected to the high-voltage equipotential open current transformer, the high-voltage equipotential voltage energy harvesting power supply module and the control module, and the capacitive energy harvesting transformer is respectively connected to the high-voltage equipotential voltage energy harvesting The power supply module is electrically connected to the low-voltage side power supply module, the voltage signal sampling module is electrically connected to the electronic voltage transformer, the control module and the low-voltage side power supply module, and the wireless communication module is connected to the control module Electrically connected, the low-voltage side power supply module is electrically connected to the control module, and the high-voltage equipotential open current transformer is arranged on the equipotential high-voltage side.

Preferably, the control module includes a controller, and the controller adopts an STM32F4 chip.

Preferably, the wireless communication module includes a GPRS module and a Zigbee wireless communication module, and both the GPRS module and the Zigbee wireless communication module are connected to the communication port of the controller.

Preferably, fuses are provided in the capacitive energy harvesting transformer and the high voltage equipotential voltage energy harvesting power supply module.

Preferably, the output end of the high-voltage equipotential current sampling module is connected to the signal input end of the control module through an optical fiber.

The beneficial effects of the present invention are:

1. The high-voltage equipotential opening current transformer adopted in the present invention has the advantages of stable operation, reliable operation and universal application.

2. The current, voltage and electric energy harvesting transformers in the present invention are all designed with three elements, and the high-voltage equipotential opening current transformer is placed on the equipotential high-voltage side, and the current collection calculation and the collection board energy supply are completed on the high-voltage side. The current collection is transmitted to the secondary side control module through optical fiber, and the basic electrical parameters such as voltage and current effective value, power and frequency can be obtained through FFT analysis, and sent to the host computer for processing through the wireless transmission module.

3. The present invention solves the problem of performance consistency and reliability of the high-voltage power collection device that can be installed with electricity, and removes technical obstacles for its large-scale use.

4. The communication module of the present invention has a GPRS module and a Zigbee wireless communication module, which can realize short-distance and long-distance wireless communication and ensure the reliability of communication.

Description of drawings

Fig. 1 is a composition structure block diagram of the present invention;

Fig. 2 is the composition block diagram of control module of the present invention;

Fig. 3 is a circuit schematic diagram of a high voltage equipotential voltage energy harvesting power supply module;

In the figure: 1-A phase detection unit, 2-B phase detection unit, 3-C phase detection unit, 4-control module, 5-wireless communication module, 6-low voltage side power supply module, 11-high voltage equipotential opening Current transformer, and, 12-high voltage equipotential current sampling module, 13-capacitive energy transformer, 14-high voltage equipotential voltage energy harvesting power supply module, 15-electronic voltage transformer, 16-voltage signal sampling module.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, the present invention includes a phase A detection unit 1, a B phase detection unit 2, a C phase detection unit 3, a control module 4, a wireless communication module 5 and a low voltage side power supply module 6, A phase detection unit 1, The B-phase detection unit 2 and the C-phase detection unit 3 both include a high-voltage equipotential open-ended current transformer 11, a high-voltage equipotential current sampling module 12, a capacitive energy-taking transformer 13, a high-voltage equipotential voltage energy-taking power supply module 14, an electronic The voltage transformer 15 and the voltage signal sampling module 16, the high-voltage equipotential current sampling module 12 are electrically connected with the high-voltage equipotential open current transformer 11, the high-voltage equipotential voltage energy harvesting power supply module 14 and the control module respectively, and the capacitive energy harvesting transformer 13 are respectively electrically connected to the high-voltage equipotential voltage energy harvesting power supply module 14 and the low-voltage side energy supply power supply module 6, and the voltage signal sampling module 16 is electrically connected to the electronic voltage transformer 15, the control module and the low-voltage side energy supply power supply module 6 respectively, The wireless communication module 5 is electrically connected to the control module, the low-voltage side power supply module 6 is electrically connected to the control module, the high-voltage equipotential opening current transformer 11 is arranged on the equipotential high-voltage side, and the capacitive energy-taking transformers 13 are respectively high-voltage equipotential The voltage energy acquisition power supply module 14 and the low voltage side energy supply power supply module 6 supply electric energy.

The high-voltage equipotential open-ended current transformer 11 is provided with an open-ended Rogowski coil. The open-ended Rogowski coil performs current measurement based on the principle of electromagnetic induction, and indirectly measures the current value by inducing the change of the magnetic field around the primary conductor (ie, the primary winding). The open-ended Rogowski coil Functions as a basic sensitive element.

The high-voltage equipotential voltage energy harvesting power supply module 14 performs voltage measurement based on the principle of series capacitor voltage division, divides the voltage through the distribution of the capacitance value of the high and low voltage arms, and measures the voltage value by measuring the change of the voltage at the end of the low voltage arm. The voltage-dividing capacitor serves the function of the basic sensing element.

The capacitive energy harvesting transformer 13 also performs voltage division based on the principle of series capacitor voltage division, the difference is that it is regarded as a current source, and the current is obtained through the low-voltage arm.

The control module 4 includes a controller, and the controller adopts an STM32F4 chip. The output end of the high-voltage equipotential current sampling module 12 is connected to the signal input end of the control module 4 through an optical fiber to ensure that the signal is free from external electromagnetic interference. The wireless communication module 5 includes GPRS module and Zigbee wireless communication module 5, GPRS module and Zigbee wireless communication module 5 are all connected with the communication port of controller by signal line, according to the distance requirement of communication distance, can select different communication modes.

Both the high-voltage equipotential current sampling module 12 and the voltage signal sampling module 16 have a signal conditioning circuit inside. The signal conditioning circuit includes a signal amplification circuit and an A/D conversion circuit. The voltage and current signals collected by the transformer are transformed after being processed by the signal conditioning circuit. It is a digital signal that the controller can recognize and process.

Both the capacitive energy harvesting transformer 13 and the high voltage equipotential voltage energy harvesting power supply module 14 are provided with fuses, which can effectively protect the capacitive energy harvesting transformer 13 and the high voltage equipotential voltage energy harvesting power supply module when a short circuit occurs in the line 14 for security.

The composition and structure of the control module is shown in Figure 2. The controller receives the digital signals collected by the voltage signal sampling module 16 and the high-voltage equipotential current sampling module 12, performs interpolation synchronization processing, and obtains the voltage and current effective value, power and frequency through FFT analysis Such basic electrical parameters, electric energy, voltage and current harmonic harmonic power and other electric power quality parameters are stored in the non-volatile memory after preliminary statistical analysis. And the communication module can receive remote commands through GPRS, and send out the data stored in the non-volatile memory.

The electrical schematic diagram of the high-voltage equipotential voltage energy harvesting power supply module 14 is shown in Figure 3. The high-voltage arm capacitor C1 and the low-voltage arm capacitor C2 form a voltage divider, which divides the high-voltage input HV into the voltage range that the subsequent circuit can withstand. The low voltage obtained by the voltage is output from both ends of C2, rectified into DC by rectifier bridge B and filtered by C3 to obtain relatively smooth DC high voltage, and then converted into secondary signal processing circuit by DC/DC (DC/DC) converter, which can be directly The 5V voltage used, the Zener diode D is used to limit the rectified DC high voltage amplitude to protect the DC/DC converter.

Finally, it is noted that the above embodiments are only used to illustrate the technical solution of the present invention and not to limit it. Those of ordinary skill in the art may make other modifications or equivalent replacements to the technical solution of the present invention, as long as they do not depart from the spirit and spirit of the technical solution of the present invention. All should be included in the scope of the claims of the present invention.

Claims (5)

1. A PT and CT combination device that can be installed with electricity is characterized in that: it includes a phase A detection unit, a B phase detection unit, a C phase detection unit, a control module, a wireless communication module and a low-voltage side energy supply power supply module, the A phase detection unit, B phase detection unit and C phase detection unit all include high voltage equipotential open current transformer, high voltage equipotential current sampling module, capacitive energy transformer, high voltage equipotential voltage energy harvesting power supply module, electronic voltage A transformer and a voltage signal sampling module, the high-voltage equipotential current sampling module is electrically connected to the high-voltage equipotential open current transformer, the high-voltage equipotential voltage energy harvesting power supply module and the control module, and the capacitive energy harvesting transformer is respectively connected to the The high-voltage equipotential voltage energy harvesting power supply module is electrically connected to the low-voltage side energy supply power supply module, the voltage signal sampling module is electrically connected to the electronic voltage transformer, the control module, and the low-voltage side energy supply power supply module, and the wireless communication The module is electrically connected to the control module, the low-voltage side power supply module is electrically connected to the control module, and the high-voltage equipotential open current transformer is arranged on the equipotential high-voltage side. 2. The live-installable PT and CT combination device according to claim 1, characterized in that: the control module includes a controller, and the controller adopts an STM32F4 chip. 3. according to claim 1 and 2 described PT, CT combination device that can be installed with electricity, it is characterized in that: described wireless communication module comprises GPRS module and Zigbee wireless communication module, and described GPRS module and Zigbee wireless communication module are all connected with The communication port of the controller is connected. 4. The live-installable PT and CT combination device according to claim 1, characterized in that fuses are provided in the capacitive energy harvesting transformer and the high-voltage equipotential voltage energy harvesting power supply module. 5. The live-installable PT and CT combined device according to claim 1, characterized in that: the output end of the high-voltage equipotential current sampling module is connected to the signal input end of the control module through an optical fiber.