CN103441725A - System for monitoring and controlling grounding currents of transformer core - Google Patents

Abstract

The invention discloses a transformer iron core grounding current monitoring and control system, which includes a transformer, a current acquisition unit, a single-chip microcomputer, and a control module. , a control module, the control module includes a motor, a rotating device and an adjustable resistor, the two current input terminals of the current acquisition unit are respectively connected to the upper ends of two fuses, and the fuses are arranged on the ground wire of the transformer core and the grounding line of the transformer plus part, the two output terminals of the adjustable resistor are respectively connected to the lower ends of the two fuses. When the current detected by the present invention is greater than the rated value stored in the microcontroller, the microcontroller automatically controls the control circuit to Adjust the resistance to adjust until the transformer core current is less than the rated current stored in the single-chip microcomputer, which reduces the workload of the operator and reduces the impact of the excessive current on the power consumption of the power user between the two detections of the equipment.

Description

Transformer core ground current monitoring and control system

the

Technical field:

The invention relates to a grounding current monitoring and control device, in particular to a transformer iron core grounding current monitoring and control system.

Background technique:

State Grid stipulates that 110KV level transformers should be tested once a year, and transformers with 220KV level and above should be tested twice a year. It is required that the transformer core current during operation should not exceed 0.1A. During the live test every year, the operator uses an ordinary clamp ammeter to measure the transformer. The current value of the iron core grounded flat iron, and record. The disadvantages of this method are that ordinary current clamps have low measurement accuracy, are susceptible to interference, and the time interval between two preventive inspections is long, making it difficult to find sudden ground current overrun faults.

During detection, when the transformer core ground current value exceeds the specified 0.1A, the operator usually disconnects the core ground wire, connects an adjustable resistor and ammeter in series, manually adjusts the resistance, and observes the value of the ammeter until it is lower than 0.1A. Then replace the adjustable resistor with a high-power resistor with fixed resistance, remove the ammeter, restore the grounding lead, and wait for overhaul. The disadvantage of this method is that the temporary processing process is complicated and takes a long time, the series resistance circuit does not have waterproof function, the overhaul and inspection cycle is long, and it cannot be guaranteed that the transformer core current will not exceed 0.1A again during the waiting period for overhaul.

the

Invention content:

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a simple and practical transformer core ground current monitoring and control system capable of real-time detection and control of the transformer core ground current.

The technical solution of the present invention is: a transformer core grounding current monitoring and control system, including a transformer, a current acquisition unit, a single-chip microcomputer, and a control module, wherein: the transformer is connected to the current collection unit, and the single-chip microcomputer has two interface modules, respectively It is connected with the current acquisition unit and the control module, and the control module includes a motor, a rotating device and an adjustable resistance.

The two current input terminals of the current acquisition unit are respectively connected to the upper ends of two fuses, the fuses are arranged on the transformer core ground wire and the transformer add-on ground wire, and the two output terminals of the adjustable resistor are respectively connected to the The lower end of the two fuses. The single-chip microcomputer is connected with the computer of the control center through the communication module and the electric power APN private network. The connecting wires between the current acquisition unit, the transformer and the single-chip microcomputer are 2-core shielded wires, and the single-chip microcomputer, the communication module, the current collection unit, and the control module are provided with waterproof and anti-electromagnetic facilities. The single-chip microcomputer is connected with the current acquisition unit through the RS485 interface, and provides 24V voltage.

The beneficial effects of the present invention are:

1. When the current detected by the present invention is greater than the rated value stored in the control circuit, the data is sent to the computer in the control center through the power APN private network in the form of GPRS wireless transmission, and the operator is reminded to maintain the equipment in time. APN private network transmission data guarantees the accuracy and security of communication data.

2. When the current detected by the present invention is greater than the rated value stored in the single-chip microcomputer, the single-chip microcomputer automatically controls the control circuit to adjust the adjustable resistance until the transformer core current is less than the rated current stored in the single-chip microcomputer. Work burden, reduce the impact on the power consumption of power users due to excessive current between two detections of equipment.

3. The installation of the system of the present invention does not change the wiring and grounding mode of the original power equipment, and will not cause any interference or influence on the primary system, and the electromagnetic shielding shell is used to prevent the magnetic field generated by the transformer from affecting the detection and control accuracy of the equipment .

4. The present invention is equipped with a fuse. When the current on the ground wire of the transformer core and the ground wire of the transformer add-on exceeds a certain value, it will automatically fuse, cut off the original ground wire, and connect the automatic current control device to the transformer core and the transformer. In the addition of the ground wire, the automation of the operation is realized.

5. The invention is simple and practical, can detect and control the ground current of the transformer iron core in real time, has a wide application range, is convenient for operators to operate, saves manpower and material resources, and is easy to popularize and implement.

Description of drawings:

Figure 1 is a connection schematic diagram of the transformer core ground current monitoring and control system.

Detailed ways:

Embodiment: See Figure 1, in the figure, 1-transformer core ground wire, 2-transformer splint ground wire, 3-fuse, 4-current acquisition unit, 5-single-chip microcomputer, 6-communication module, 7-motor, 8 -Adjustable resistance, 9-Control center computer, 10-Transformer, 11-Waterproof, anti-electromagnetic box.

Transformer core grounding current monitoring and control system: it includes a transformer 10, a current acquisition unit 4, a single-chip microcomputer 5, and a control module, wherein: the transformer 10 is connected to the current acquisition unit 4, and the single-chip microcomputer 5 has two interface modules, respectively connected to the current acquisition unit 4. The control module is connected, and the control module includes a motor 7, a rotating device and an adjustable resistor 8.

The two current input ends of the current acquisition unit 4 are respectively connected to the upper ends of two fuses 3, the fuses 3 are set on the transformer core ground wire 1 and the transformer add-on ground wire 2, and the two output ends of the adjustable resistor 8 are respectively Connected to the lower ends of the two fuses 3.

The single-chip microcomputer 5 is connected with the computer of the control center through the communication module 6 and the electric power APN private network.

The connecting wires between the current collection unit 4, the transformer 10 and the single-chip microcomputer 5 are 2-core shielded wires, and the outside of the single-chip microcomputer 5, the communication module 6, the current collection unit 4, and the control module are provided with waterproof and anti-electromagnetic facilities.

The single-chip microcomputer 5 is connected with the current acquisition unit 4 through the RS485 interface, and provides 24V voltage.

When in use, the upper ends of the fuse 3 on the transformer core ground wire 1 and the transformer add-on ground wire 2 are respectively connected to the two current input ports of the current acquisition unit 4, and the current acquisition unit 4 sends the detected electrical signal to the In the single-chip microcomputer 5, the single-chip microcomputer 5 compares the value of the input electrical signal according to the stored rated value. If the input electrical signal value is less than the stored rated value, the device continues to run. If the input electrical signal value is greater than the stored rated value, then The single-chip microcomputer 5 sends the input electrical signal value to the computer in the control center through the power APN private network and GPRS wireless transmission mode, and at the same time automatically controls the motor 7 to adjust the adjustable resistor 8 until the transformer core current is less than the value stored in the single-chip microcomputer 5 up to the rated current.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still belong to within the scope of the technical solutions of the present invention.

Claims (5)

1. A transformer iron core grounding current monitoring and control system comprises a transformer, a current acquisition unit, a single-chip microcomputer, and a control module, and is characterized in that: the transformer is connected with the current acquisition unit, and the single-chip microcomputer has two interface modules, respectively connected to the current acquisition unit A unit and a control module are connected, and the control module includes a motor, a rotating device and an adjustable resistance. 2. The transformer core grounding current monitoring and control system according to claim 1, characterized in that: the two current input terminals of the current acquisition unit are respectively connected to the upper ends of two fuses, and the fuses are arranged on the transformer The two output terminals of the adjustable resistor are respectively connected to the lower ends of the two fuses on the ground wire of the iron core and the ground wire of the transformer add-on. 3. The transformer core grounding current monitoring and control system according to claim 1, characterized in that: the single-chip microcomputer is connected to the computer in the control center through the communication module and the electric power APN private network. 4. The transformer core grounding current monitoring and control system according to claim 1, characterized in that: the connection wires between the current acquisition unit and the transformer and the single-chip microcomputer are 2-core shielded wires, and the single-chip microcomputer, communication module , The current collection unit and the control module are equipped with waterproof and anti-electromagnetic facilities. 5. The transformer core grounding current monitoring and control system according to claim 1, characterized in that: the single-chip microcomputer and the current acquisition unit are connected through an RS485 interface and provide 24V voltage.

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