CN221614639U - Electrical system of high voltage incoming line equipment with power-on buffering function - Google Patents

Abstract

The utility model discloses a high-voltage wire inlet equipment electrical system with a power-on buffering function, which comprises an input end, wherein the input end is sequentially connected with a current transformer and a disconnecting switch in series and then connected to an equipment bus, a voltage transformer is connected in parallel on a connecting circuit between the input end and the current transformer, the equipment bus is connected with a vacuum circuit breaker and a vacuum contactor in parallel through two branches and then connected to an output end through a main circuit, and a high-voltage resistor is connected in series on a branch where the vacuum contactor is located. The high-voltage wire inlet equipment electrical system with the power-on buffer function greatly reduces the highest value of steady magnetic flux when the high-voltage side of the high-capacity transformer in the system is electrified, and shortens the transient duration time of the exciting surge current of the transformer, so that the stable power-on operation of the transformer is ensured, the false tripping phenomenon caused by the exciting surge current when the transformer transmits power is avoided, and the damage to other power electronic equipment and the impact to the field bus voltage when the transformer is put into operation are avoided.

Description

Electrical system of high voltage incoming line equipment with power-on buffering function

Technical Field

The utility model belongs to the technical field of high-voltage power distribution systems, and in particular relates to an electrical system of high-voltage incoming line equipment with a power-on buffering function.

Background Art

In recent years, the power source of each link of oil and gas production operations has gradually been replaced by grid electricity. Domestic power equipment manufacturers have also launched electric drive production equipment of different powers, which greatly saves customers equipment purchase costs, fuel costs and wearing parts costs, and achieves diesel-free and zero emissions. Among them, the high-voltage and high-power frequency conversion control system is an important product in electric drive equipment. The large-capacity high-voltage transformer equipped with it provides a stable working power supply for the high-power frequency conversion module, and the 6kV medium-voltage power supply generated by the high-power frequency conversion module provides the on-site load equipment with power energy that can adjust the frequency according to the working conditions. However, the products on the market currently generally have the following problems:

First, when a large-capacity transformer is powered on at high voltage, it will generate a large magnetic flux, resulting in an excitation inrush current phenomenon. The excitation inrush current has a large value, which can reach 8 to 10 times the rated current. In addition, the inrush current contains a large value of high-order harmonic components (mainly second and third harmonics), and the excitation inrush current curve is a peak wave. Therefore, when the transformer is powered on and closed, the following adverse effects will occur: 1) Due to the excitation inrush current, the high-voltage switch may trip frequently and power cannot be delivered smoothly; 2) The transformer is charged multiple times by continuous closing and charging, and the multiple impacts of large current will cause mechanical forces between the windings, which may gradually loosen the fixings and damage the transformer; 3) Excessive starting current and harmonics may cause the power electronic equipment on the bus to be impacted and damaged.

Secondly, when high-voltage power equipment, especially transformers, are in operation, it is necessary to judge the operating status of the equipment based on the current real-time power values, and to issue alarms and trip in time when a fault occurs, thereby effectively protecting each device and protecting the safety of personnel.

Finally, an AC220V power supply needs to be designed to ensure that the instruments and control systems on site can be powered on and started when there is no low-voltage control power supply on site.

Therefore, researching a high-voltage incoming line device with power-on buffering function can not only ensure the smooth power-on operation of the transformer, avoid the false tripping caused by the excitation surge current when the transformer is powered on, and avoid damage to other power electronic equipment and impact on the on-site bus voltage when the transformer is put into use, but also has high-voltage protection, transformer non-electrical protection function, can connect to 10kV input, and has its own control power supply. This is a new direction that needs to be studied at present.

Utility Model Content

The utility model aims to provide an electrical system of high-voltage incoming line equipment with a power-on buffering function, thereby solving the problem that the existing large-capacity transformer has a large impact when the high voltage is powered on.

The technical scheme adopted by the utility model is: an electrical system of a high-voltage incoming line equipment with a power-on buffer function, comprising an input end, the input end is connected to the equipment bus after being connected in series with a current transformer and an isolating switch in sequence, a voltage transformer is connected in parallel on the connection line between the input end and the current transformer, a vacuum circuit breaker and a vacuum contactor are connected in parallel on the equipment bus through two branches and then connected to the output end by a main line, and a high-voltage resistor is connected in series on the branch where the vacuum contactor is located.

The utility model is also characterized in that:

A high voltage lightning arrester is also connected in parallel on the connection line between the input end and the current transformer.

A high-voltage sensor is also connected in parallel to the connection line between the input end and the current transformer, and a high-voltage live display is connected to the high-voltage sensor.

The output lines of the current transformer and the voltage transformer are commonly connected with a transformer integrated protection device.

The output lines of the current transformer and the voltage transformer are commonly connected with a multifunctional electric power meter.

The beneficial effects of the utility model are as follows: the electrical system of the high-voltage incoming line equipment with power-on buffering function of the utility model greatly reduces the maximum value of the steady-state magnetic flux when the high-voltage side of the large-capacity transformer in the system is powered on, and at the same time shortens the transient duration of the transformer excitation surge current, thereby ensuring the smooth power-on operation of the transformer, avoiding the false tripping caused by the excitation surge current when the transformer is powered on, and avoiding damage to other power electronic equipment and impact on the on-site bus voltage when the transformer is put into use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of an electrical system of a high-voltage incoming line device with a power-on buffering function according to the present invention.

In the figure, 1. voltage transformer, 2. current transformer, 3. high-voltage sensor, 4. isolating switch, 5. vacuum circuit breaker, 6. vacuum contactor, 7. high-voltage resistor, 8. high-voltage lightning arrester, 9. high-voltage live display, 10. transformer integrated protection device, 11. multi-functional power meter.

DETAILED DESCRIPTION

The utility model is described in detail below with reference to the accompanying drawings and specific implementation modes.

Example 1

The utility model provides an electrical system of a high-voltage incoming line equipment with a power-on buffering function, which is suitable for a voltage level of 3 to 35 kV. Taking access to a 10 kV power supply as an example, as shown in FIG1 , the system comprises a 10 kV input terminal, the 10 kV input terminal is sequentially connected in series with a 10 kV current transformer 2 and a 10 kV isolating switch 4 and then connected to an equipment busbar, a 10 kV voltage transformer 1 is connected in parallel on a connection line between the 10 kV input terminal and the 10 kV current transformer 2, a 10 kV vacuum circuit breaker 5 and a 10 kV vacuum contactor 6 are connected in parallel on the equipment busbar through two branches and then connected to a 10 kV output terminal through a main line, and a 10 kV high-voltage resistor 7 is connected in series on the branch where the 10 kV vacuum contactor 6 is located.

Among them, the 10kV voltage transformer 1 uses the principle of electromagnetic induction to convert the system's 10kV high voltage into an AC 100V voltage that can be used for control systems, instruments, and protection collection. At the same time, the 10kV voltage transformer also has a built-in set of AC 220V windings, which can provide operating power for the equipment's instruments, protection and control systems, providing great convenience for sites without low-voltage control power supplies.

The 10kV current transformer 2 also uses the principle of electromagnetic induction to convert the large current of the system into a small current within AC 5A that can be used for control system, instrumentation and protection collection.

The 10kV isolating switch 4 is the main switch of the high-voltage incoming line equipment, which has the function of disconnecting and connecting the high-voltage circuit. As a switch with a clear breakpoint, it provides convenience for the equipment in various aspects of later maintenance, use, inspection, safety, etc.

The 10kV vacuum circuit breaker 5 is named because its arc extinguishing medium and the insulating medium of the contact gap after arc extinguishing are both high vacuum. It has the advantages of small size, light weight, suitable for frequent operation, and no need for maintenance after arc extinguishing. It can interrupt fault current and play the role of interrupting the high voltage power supply of the transformer and protecting the transformer.

The 10kV vacuum contactor 6 is mainly composed of a vacuum interrupter and an operating mechanism. The vacuum interrupter has two functions: passing the normal working current and reliably extinguishing the arc when frequently cutting off the working current, and serves as a switch for the transformer pre-charging circuit.

The main function of the 10kV high voltage resistor 7 is to hinder the flow of current. It is used in current limiting, current shunting, voltage reduction, voltage division, load and capacitor matching as filters, etc.

Through the above-mentioned method, the electrical system of the high-voltage incoming line equipment with power-on buffering function of the utility model greatly reduces the maximum value of the steady-state magnetic flux when the high-voltage side of the large-capacity transformer in the system is powered on, and at the same time shortens the transient duration of the transformer excitation surge current, thereby ensuring the smooth power-on operation of the transformer, avoiding the false tripping caused by the excitation surge current when the transformer is powered on, and avoiding damage to other power electronic equipment and impact on the on-site bus voltage when the transformer is put into use.

Example 2

A high voltage arrester 8 is also connected in parallel to the connection line between the 10kV input terminal and the 10kV current transformer 2. The function of the high voltage arrester 8 is to protect the electrical equipment from high transient overvoltage hazards and limit the follow-through time and often also limit the follow-through amplitude.

A 10kV high-voltage sensor 3 is also connected in parallel to the connection line between the 10kV input terminal and the 10kV current transformer 2, and a high-voltage live display 9 is connected to the 10kV high-voltage sensor 3. The high-voltage live display 9 is generally used in places where it is necessary to display whether the high voltage is live. It is an instrument that can visually monitor whether the high-voltage bus is live, and has a locking function to prevent electrical misoperation. It is generally used in conjunction with an electromagnetic lock. When the high voltage is live, the electromagnetic lock cannot be operated, and the door of the live compartment cannot be opened, ensuring the safety of personnel.

The output lines of the 10kV current transformer 2 and the 10kV voltage transformer 1 are commonly connected with a transformer comprehensive protection device 10 and a multifunctional power meter 11. The transformer comprehensive protection device 10 is an intelligent relay protection device that performs real-time protection on the transformer by monitoring the operating parameters of the transformer. It mainly has: three-stage compound voltage overcurrent protection, inverse time overcurrent protection, two-stage definite time negative sequence overcurrent protection, definite time zero sequence overcurrent protection on the high-voltage side, definite time zero sequence overcurrent protection on the low-voltage side, inverse time zero sequence overcurrent protection on the low-voltage side, overload protection, overvoltage protection, low voltage protection, non-electrical quantity protection, FC interlocking, etc. The multifunctional power meter 11 has multiple functions such as programmable measurement, display, digital communication and electric energy pulse transmission output, and can complete electric quantity measurement, electric energy metering, data display, collection and transmission, etc.

Through the above-mentioned method, the high-voltage incoming line equipment of the utility model not only completes the reception and output of 10kV power supply, but also sets up multiple groups of 10kV high-voltage sensors 3 and high-voltage live displays 9 at the same time, so that users can clearly observe the high-voltage live conditions of each voltage level and each position and complete electrical interlocking, ensure the safety of equipment and personnel, and protect electrical equipment from high transient overvoltage hazards and limit the follow-up time and amplitude through the high-voltage lightning arrester 8. At the same time, the high-voltage incoming line equipment can also design a group of AC 220V windings in the voltage transformer 1 on the 10kV incoming line side, and design protection and measurement windings within 5A in the 10kV current transformer 2, which can provide small voltage and small current signals that can be monitored for the transformer comprehensive protection device 10 and the multifunctional power meter 11, thereby providing operating power for the equipment's instrument, protection and control system, which provides great convenience for sites without low-voltage control power supply.

Example 3

During operation, ① first close the 10kV isolating switch 4 of this equipment, the 10kV high-voltage power supply on site is supplied to the bus of the equipment, the 10kV voltage transformer 1 is energized to generate AC220V and AC100V voltages, and at the same time, the 10kV current transformer 2 is energized to generate a small current within 5A that can be collected by the multi-functional power meter 11, and then the multi-functional power meter 11 is energized to operate, and the meter displays the voltage value; the 10kV high-voltage sensor 3 is connected, and the 10kV incoming high-voltage energized display 9 lights up. ② Transformer startup stage: the 10kV vacuum contactor 6 is closed, and the 10kV voltage of the bus of this equipment passes through the 10kV vacuum contactor 6 and then through the 10kV high-voltage resistor 7 to enter the high-voltage side of the transformer, the transformer is started, and the multi-functional power meter 11 displays various power operation parameters of the transformer in real time. ③ Normal operation stage of transformer: After the transformer is started by the 10kV high-voltage resistor 7, after about 5 to 10 seconds (the time can be set), the 10kV vacuum circuit breaker 5 is closed, and then the 10kV vacuum contactor 6 is disconnected. The 10kV bus voltage of this equipment directly enters the high-voltage side of the transformer through the 10kV vacuum circuit breaker 5. The transformer operates normally, and the multi-function power meter 11 displays various power operation parameters of the transformer in real time. ④ Regardless of whether it is the transformer startup stage or the normal operation stage, the transformer comprehensive protection device 10 monitors and protects the operating status of the transformer. If overvoltage, undervoltage, short circuit, overcurrent, high temperature and overtemperature faults occur, an alarm or tripping can be issued; the high-voltage lightning arrester 8 can also be grounded for protection in the event of high transient overvoltage.

Claims (5)

1. The utility model provides a high-voltage wire inlet equipment electrical system with power-on buffer function, a serial communication port, including the input, be connected to the equipment generating line behind input series connection current transformer (2) and isolator (4) in proper order, parallelly connected on the connecting wire between input and current transformer (2) has voltage transformer (1), is connected to the output by the trunk after connecting vacuum circuit breaker (5) and vacuum contactor (6) through two branch road in parallel on the equipment generating line, vacuum contactor (6) place branch road on-line has high-voltage resistor (7) in series.

2. The high-voltage wire-feeding equipment electrical system with the power-on buffering function according to claim 1, wherein a high-voltage lightning arrester (8) is further connected in parallel on a connecting line between the input end and the current transformer (2).

3. The high-voltage wire-feeding equipment electrical system with the power-on buffering function according to claim 1, wherein a high-voltage sensor (3) is further connected in parallel on a connecting line between the input end and the current transformer (2), and a high-voltage live display (9) is connected to the high-voltage sensor (3).

4. The high-voltage wire-feeding equipment electrical system with the power-on buffering function according to claim 1, wherein the output wires of the current transformer (2) and the voltage transformer (1) are commonly connected with a transformer comprehensive protection device (10).

5. The high-voltage wire-feeding equipment electrical system with the power-on buffering function according to claim 1, wherein the output wires of the current transformer (2) and the voltage transformer (1) are commonly connected with a multifunctional electric instrument (11).