CN212366837U

CN212366837U - Power grid synchronous phase modulator system

Info

Publication number: CN212366837U
Application number: CN202020848967.6U
Authority: CN
Inventors: 王卓林; 汪孔屏; 卢晨; 顾万里; 吴海斌
Original assignee: Construction Consulting Branch Of China Online Shanghai Electric Power Co; State Grid Shanghai Electric Power Co Ltd
Current assignee: Construction Consulting Branch Of China Online Shanghai Electric Power Co; State Grid Shanghai Electric Power Co Ltd
Priority date: 2020-05-20
Filing date: 2020-05-20
Publication date: 2021-01-15
Anticipated expiration: 2030-05-20

Abstract

The utility model discloses a synchronous phase modulation machine system of electric wire netting, including phase modulation machine body, excitation system, phase modulation machine start-up system and high-voltage bus, this body coupling of phase modulation machine the excitation system, excitation system connects the start power auto-change over device, start power auto-change over device is the double switch, connects two sets of exciting transformer respectively, and wherein a set of exciting transformer inserts 380v station power consumption, and another set of exciting transformer connects phase modulation machine body and phase modulation machine start-up system respectively and inserts step-up transformer, through step-up transformer inserts high-voltage bus, phase modulation machine start-up system inserts 10kv station power consumption; the phase modifier body is grounded through a neutral point grounding cabinet. The utility model discloses can improve power factor to system transport reactive power, reduce the loss in the network, have better effect to adjustment network voltage and improvement electric energy quality.

Description

Power grid synchronous phase modulator system

Technical Field

The utility model relates to a synchronous phase modulation machine system of electric wire netting for special high voltage electric wire netting field.

Background

In recent years, with the development of a large-capacity and long-distance ultrahigh voltage alternating current and direct current transmission technology, power grid resources are optimally configured, but the outstanding problems brought by the power grid are that the power grid is strong direct current and weak alternating current, the power receiving proportion of a local power grid is high, the dynamic reactive power compensation of the system is insufficient, and the voltage stability problem is obvious. The main performance is as follows:

(1) the problem of insufficient dynamic reactive power of an extra-high voltage direct current receiving end power grid is outstanding: because the direct current does not provide dynamic reactive power for the system, the reactive power of the receiving-end power grid is insufficient, and a large amount of reactive power needs to be absorbed from the system in the dynamic process. With the large-scale feeding of direct current, the problem of voltage stability of a receiving-end power grid becomes more prominent.

(2) Short-circuit capacity of a direct-current weak sending end system is insufficient: along with the extension of the development of large-scale energy bases to remote areas, particularly the large-scale centralized development of wind power and photovoltaic, the problems of weak power grid and insufficient short-circuit capacity of a direct-current transmission end are obvious, on one hand, the improvement of the direct-current transmission capacity is seriously dependent on the starting mode of the thermal power of the transmission end, and the clean energy consumption and the flexibility of the power grid operation mode are directly influenced; on the other hand, the transient voltage of a sending end system is increased due to the failure of direct current commutation, and the large-area off-line of the fan is caused under the serious condition.

(3) The high-proportion power-receiving area has insufficient voltage support, thermal power generating units in areas such as Beijing and Tianjin are gradually shut down according to the national atmospheric pollution control action plan, part of load is supplied by a gas generating unit, and meanwhile, the external power receiving proportion is continuously increased along with the further increase of the load. The contradiction of insufficient voltage support is prominent, and particularly, when a gas pipeline breaks down, the gas turbine set is forced to stop running, so that the problem of voltage stability is easily caused, and the power supply safety of key areas is seriously threatened.

In order to solve the problems, direct current large-scale active power transmission is objectively required, and large-scale dynamic reactive power must be matched.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming prior art's not enough, provide a synchronous phase modulation machine system of electric wire netting, it can be to system transport reactive power, improves power factor, reduces the loss in the network, has better effect to adjustment network voltage and improvement electric energy quality.

One technical scheme for achieving the above purpose is as follows: a power grid synchronous phase modulator system comprises a phase modulator body, an excitation system, a phase modulator starting system and a high-voltage bus;

the phase modifier body is connected with the excitation system, the excitation system is connected with a starting power supply switching device, the starting power supply switching device is a duplex switch and is respectively connected with two groups of excitation transformers, one group of the excitation transformers are connected with a 380v station for power utilization, the other group of the excitation transformers are respectively connected with the phase modifier body and the phase modifier starting system and are connected with a step-up transformer, a high-voltage bus is connected through the step-up transformer, and the phase modifier starting system is connected with a 10kv station for power utilization;

the phase modifier body is grounded through a neutral point grounding cabinet.

Further, still include respectively with cooling system and oil system that the phase modifier body is connected.

Furthermore, the rotor of the phase modulator body is a non-salient pole type rotor, the phase modulator body is of an inner base structure and an outer base structure, the outer base is divided into two halves from top to bottom, the cooler is horizontally arranged in a foundation pit in the upper half base and below the base, and an elliptical tile seat type bearing is adopted.

Furthermore, the excitation system adopts a static excitation system and consists of an excitation regulator, a silicon controlled rectifier, a de-excitation and overvoltage protection device and an excitation transformer.

Furthermore, the phase modulator starting system adopts a starting system of a static frequency converter starting mode.

Furthermore, the step-up transformer adopts no-load voltage regulation.

The utility model discloses a synchronous phase modulation machine system of electric wire netting, can let its excitation operation when the electric wire netting is loaded, reduce the reactive current component that lags in the power transmission line to reducible line pressure drop; under the condition of light load of the power transmission line, the power transmission line is under-excited to run, so that lagging reactive current is absorbed, the voltage of the power grid can be prevented from rising, the voltage of the power grid is maintained at a certain level, and the power transmission line also has the function of improving the stability of a power system.

Drawings

Fig. 1 is a schematic diagram of a system architecture of a power grid synchronous phase modulation system according to the present invention.

Detailed Description

In order to better understand the technical solution of the present invention, the following detailed description is made by specific embodiments:

referring to fig. 1, the utility model discloses a synchronous phase modulation machine system of electric wire netting, including phase modulation machine body 1, excitation system 2, phase modulation machine start-up system 3 and high-voltage bus 4.

The phase modifier rotor comprises a salient pole and a non-salient pole, and is combined with an application scene of an extra-high voltage power grid, the rotor of the phase modifier body 1 is a non-salient pole type rotor, the phase modifier body is of an inner and outer base structure, the outer base is divided into two halves from top to bottom, a cooler is horizontally arranged in foundation pits in the upper half base and below the base, and an elliptical tile base type bearing is adopted. The phase modifier body 1 is respectively connected with a cooling system 11 and an oil system 12. The phase modulator body 1 is grounded through a neutral point grounding cabinet 13.

The phase modifier body 1 is connected with an excitation system 2. The excitation system 2 includes static excitation, brushless excitation, three-machine excitation, and the like. The static excitation system is adopted by combining the application scene of the extra-high voltage power grid, the shafting is short, the building area and the occupied area of a main plant are small, the reliability is high, the maintenance amount is small, and the response speed is high. The excitation system adopts a self-shunt excitation mode. The excitation system consists of an excitation regulator, a silicon controlled rectifier, a de-excitation and overvoltage protection device and an excitation transformer. The excitation power supply is taken from the machine end, is connected to the silicon controlled rectifier device through the excitation transformer, is rectified into direct current, and is connected to the rotor winding for excitation after passing through the field suppression switch. The excitation regulator automatically regulates and controls the direct current output of the silicon controlled rectifier device according to the terminal voltage and the reactive power signal and according to a set value so as to control the terminal voltage and the reactive power of the phase modulator. It has the following performance index requirements.

(1) The excitation system can meet the requirement of long-term continuous operation of the phase modulator under the working condition of 1.1 times of rated excitation current and voltage under the rated capacity.

(2) The excitation system has the capability of controlling the magnetic field voltage to positive or reverse top voltage so as to realize forced excitation and inversion de-excitation, and when the positive sequence voltage at the machine end is reduced to 80% of a rated value, 3.5 times of rated excitation voltage is still ensured.

(3) The excitation system can continuously run for 15s without damage under 2.5 times of rated excitation current.

(4) The voltage response time of the excitation system should satisfy the following conditions: rise (forced) is not more than 0.08 s; the drop (strong drop) is not more than 0.15 s.

(5) The automatic excitation regulating system ensures that the pressure regulating precision of the phase regulator is better than 0.5 percent.

(6) Under the condition of operating the phase modulator, the frequency value changes by 1%, and the automatic excitation regulating system ensures that the voltage change of the phase modulator is not more than +/-0.25% of a rated value.

(7) Under the condition that the fluctuation range of the alternating-current working power supply voltage of the automatic excitation regulating system is 55% -120% of a rated value in a short time (not longer than forced excitation duration), the excitation regulator can maintain normal operation.

(8) The power supply frequency is changed within the range of 45Hz to 55Hz, and the excitation system can maintain correct work.

(9) The automatic excitation regulating system can ensure that the setting range of the difference regulating rate of the terminal voltage of the phase modulator is +/-15 percent and is graded according to the span of 1 percent. The difference adjustment characteristic should have good linearity.

(10) The setting voltage change speed of the automatic excitation regulator and the manual control unit is not more than 1%/s of rated voltage and not less than 0.3%/s of rated voltage.

(11) The delay time of the excitation system should not be greater than 0.02 s.

(12) Within the voltage and frequency deviation range of the power supply for the station, the excitation system can ensure the long-term continuous operation of the phase modulator under the rated working condition.

(13) The excitation system should be regulated stably within the range of 70% -120% of the rated voltage of the phase modulator.

The excitation system 2 is connected with a starting power supply switching device 21, the starting power supply switching device is a duplex switch and is respectively connected with two groups of excitation transformers 22, one group of the excitation transformers are connected with a 380v station for power utilization, the other group of the excitation transformers 22 are respectively connected with a phase modifier body 1 and a phase modifier starting system 3 and are connected with a booster transformer 5, the booster transformer 5 is connected with a high-voltage bus 4, and the phase modifier starting system 3 is connected with a 10kv station for power utilization. The phase modifier starting system 3 adopts a Static Frequency Converter (SFC) starting mode, the SFC has no rotating equipment, the maintenance is simple, the sharing of two machines can be realized, and the investment is saved. The frequency conversion starting system mainly comprises an isolation transformer, a frequency conversion starting device and an SFC output switch. The starting power supply is led from the 10kV side in the station, rectified and frequency-converted by a special isolation transformer through an SFC and then input into a phase modulator stator through an isolation switch. The step-up transformer 5 adopts no-load voltage regulation, and the fluctuation range of the rated voltage and the tap standby terminal voltage is calculated and measured according to the actual situation on site. The phase modulator is used as a common dynamic reactive power compensation device and plays a role in the power grid in providing an effective technical means for the reactive voltage regulation of the power grid and realizing the inverse voltage regulation of the power grid; the method provides effective dynamic reactive power support for a high-proportion direct current powered local power grid; the range and the probability of direct current commutation failure when the alternating current power grid fails are reduced.

When the power grid receives an incoming call outside a high-proportion receiving area, if an alternating current system breaks down, the risk of system voltage instability exists. Use the utility model discloses a synchronous phase modulation machine system of electric wire netting can improve the power factor of electric wire netting, according to the difference of electric wire netting load condition, suitably adjusts the exciting current of phase modulation machine, can change the reactive power that the phase modulation machine drawn for the power factor of electric wire netting is close 1. In addition, in the long-distance transmission line, the line voltage changes along with different load conditions, if a synchronous phase modulator is arranged at the power receiving end of the transmission line, the transmission line is enabled to be over-excited to operate when the power grid is loaded, and the lagging reactive current component in the transmission line is reduced, so that the line voltage drop can be reduced; under the condition of light load of the power transmission line, the power transmission line is under-excited to run, hysteresis reactive current is absorbed, and the voltage of the power grid can be prevented from rising, so that the voltage of the power grid is maintained at a certain level, and the synchronous phase modulator also has the function of improving the stability of a power system.

It will be appreciated by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be used as limitations of the present invention, and that changes and modifications to the above described embodiments will fall within the scope of the claims of the present invention as long as they are within the spirit and scope of the present invention.

Claims

1. The utility model provides a synchronous phase modulation machine system of electric wire netting, includes phase modulation machine body, excitation system, phase modulation machine start-up system and high-voltage bus, its characterized in that:

the phase modifier body is grounded through a neutral point grounding cabinet.

2. A power grid synchronous phase modulator system as claimed in claim 1, further comprising a cooling system and an oil system respectively connected to said phase modulator body.

3. The power grid synchronous phase modulator system according to claim 1, wherein the rotor of the phase modulator body is a non-salient pole type rotor, the phase modulator body is of an inner and outer base structure, the outer base is divided into two halves from top to bottom, the cooler is horizontally arranged in the upper base half and in a foundation pit below the base, and an elliptical tile base type bearing is adopted.

4. The grid synchronous phase modulator system according to claim 1, wherein the excitation system is a static excitation system, and comprises an excitation regulator, a silicon controlled rectifier, a field suppression and overvoltage protection device, and an excitation transformer.

5. A network synchronous condenser system as claimed in claim 1 wherein the condenser start-up system is a static frequency converter start-up type start-up system.

6. A network synchronous phase modulator system as claimed in claim 1 wherein said step-up transformer employs no-load regulation.