Air-cooled phase modifier operating at negative pressure

Abstract

The utility model discloses a negative pressure operation air cooling phase modifier, which comprises a stator base, a stator unit and a rotating shaft, two ends of the rotating shaft are connected with the stator base through an end cover, and the end cover is provided with a bearing for supporting the rotating shaft and a rotary sealing mechanism for sealing the contact position of the end cover and the rotating shaft. A cavity is formed between the periphery of the stator unit and the stator base to form a cooling air path, an air cooler is installed on the cooling air path, the air cooler is connected with a cooling water system, the end cover is connected with a bearing lubricating oil system and a sealing oil control system, and the outer surface of the stator base is connected with an air control system. The rotating shaft is connected with an excitation system; according to the utility model, the internal air pressure during the operation of the phase modifier is reduced by taking measures, so that the internal air pressure is lower than the external environment air pressure, the air friction loss and the fan loss related to the air pressure and density in the phase modifier are reduced, and the efficiency and the economical efficiency of the air-cooled phase modifier during low-load operation are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of phase regulators, in particular to an air-cooled phase regulator operating under negative pressure. Background Art

[0002] A phase regulator is a rotating reactive power compensation device in the power grid. Its function is to provide or absorb reactive power from the grid, and its operating state is similar to that of a motor running at no load. The phase regulator itself carries no mechanical load and must absorb a certain amount of electrical energy from the grid during operation to offset the losses caused by its rotation. Phase regulator losses are divided into electrical losses (including stator copper loss, stator iron loss, and rotor copper loss) and mechanical losses (including air friction loss, fan blower loss, and bearing friction loss). During operation, the phase regulator is controlled by the excitation system to provide or absorb reactive power to the grid, improving the power factor and playing a vital role in regulating grid voltage and improving grid stability. Phase regulators are particularly important in ensuring the safe and stable operation of the grid, especially in the presence of ultra-high voltage long-distance transmission and a large amount of unstable renewable energy such as wind power and photovoltaic power.

[0003] Since a phase regulator draws a certain amount of electrical energy from the grid to cover its own losses during operation, this energy is ultimately converted into heat through both electrical and mechanical losses, causing the internal temperature of the phase regulator to rise. Therefore, a cooling medium is required. Air-cooled phase regulators use air as the cooling medium. This air absorbs the heat generated by internal losses and then transfers the heat to the cooling water system for removal. Air-cooled phase regulators do not require a sealed base, offer a simple structure, and are easy to operate and maintain, with low operating costs. They eliminate the risk of explosion and cooling medium leakage, offer excellent safety, and enjoy high market acceptance, making them widely used in power grids.

[0004] The air inside existing air-cooled condensers is connected to the external atmosphere, maintaining normal atmospheric pressure. The stator frame is a non-sealed, non-pressure-bearing structure, and there are no rotating seals such as seal pads at the contact between the stator end cap and the rotating shaft. This eliminates the need for a sealing oil control system or an air control system to regulate the air pressure inside the condenser. The auxiliary systems of existing air-cooled condensers are relatively simple, primarily consisting of a cooling water system, an excitation system, and a bearing lubrication oil system. During operation, the rotor rotates at a constant speed. Frictional losses are generated by friction between the rotor surface and the air, fan losses are generated by the air pumping from the rotor fan, and bearing friction losses are also generated. These three types of losses are known as mechanical losses, and their magnitude is independent of the condenser's load. Because the condenser's speed is constant, the same air friction, fan, and bearing losses are generated as long as the condenser is operating, regardless of load. Air friction and fan losses account for a significant portion of the total losses in air-cooled condensers, exceeding 40% when operating at rated load and even higher when operating at low loads. Regardless of the operating conditions under which the air-cooled phase regulator operates, at least 40% of the electrical energy absorbed from the power grid is consumed by air friction loss and fan blowing loss, and eventually converted into heat energy and carried away by the cooling water system. This part of the loss accounts for a larger proportion of the total loss during long-term low-load operation, further reducing the economic efficiency of the phase regulator operation.

[0005] Currently, a large number of phase-converters in China's power grid operate with light loads for the majority of their grid-connected operation. This generates significant mechanical losses and minor electrical losses. Due to this unique operating mode and the large proportion of mechanical losses in total losses, air-cooled phase-converters consume a significant amount of grid energy to offset mechanical losses (primarily air friction and fan losses). This results in low efficiency and poor economic performance during most of their grid-connected operation.

[0006] To improve the operating efficiency of air-cooled phase regulators, the existing method in the industry is to optimize the electromagnetic design of the phase regulator, and adopt measures such as reducing the current density of the stator coil and rotor coil, reducing the magnetic field density of the stator core, and optimizing the electromagnetic design and structural design to reduce the loss of the phase regulator. However, these measures have a very limited effect on improving efficiency, with the overall efficiency improvement being within 0.1%. They also lead to a significant increase in the consumption of materials such as copper, silicon steel sheets, and shaft forgings, an increase in the weight and size of the phase regulator, and an increase in cost and price. Utility Model Content

[0007] In order to significantly reduce the amount of electricity consumed by the air-cooled phase regulator from the grid during grid-connected operation and significantly improve the economic efficiency of the phase regulator operation, this scheme proposes an air-cooled phase regulator with negative pressure operation. During operation, the air pressure inside the phase regulator can be reduced to lower than the atmospheric pressure outside the machine, that is, the relative pressure of the air inside the machine is negative pressure. This reduces the loss of the phase regulator and improves its operating efficiency and economy.

[0008] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0009] A negative pressure air-cooled phase regulator comprises a stator frame, a stator unit and a rotating shaft.

[0010] The stator base is a closed shell structure, the stator unit is sleeved on the rotating shaft, the stator unit is fixed inside the stator base, both ends of the rotating shaft extend to the outside through the stator base, the two ends of the rotating shaft are connected to the stator base through end covers, the end covers are sealed with the stator base, the end covers are provided with bearings for supporting the rotating shaft and a rotating sealing mechanism for sealing the contact between the end cover and the rotating shaft; a cavity is provided around the stator unit and the stator base to form a cooling air path, an air cooler is installed on the cooling air path, the air cooler is connected to a cooling water system, the end cover is connected to a bearing lubricating oil system and a sealing oil control system, a connecting flange is provided on the outer surface of the stator base, the connecting flange is connected to an air control system, and the output end of the rotating shaft is connected to an excitation system outside the stator base.

[0011] Furthermore, the air control system includes a negative pressure blower, a pressure sensor, a pressure controller, and a vent valve. The negative pressure blower is connected to the connecting flange via a pipe, the stator frame is connected to the vent valve and the pressure sensor, and the pressure controller is electrically connected to the negative pressure blower, the pressure sensor, and the vent valve. When the condenser is operating at low load, the negative pressure blower extracts some of the air inside the machine to create a negative pressure, thereby reducing losses in the condenser. When the condenser load increases, the air control system can introduce air into the machine through the vent valve to increase the air pressure inside the machine. When the condenser is operating at rated load, the air pressure inside the machine can be increased to the same as the external atmospheric pressure to enhance the cooling capacity of the air inside the machine, ensuring that the temperature of various parts of the condenser does not exceed the standard limit when the condenser operates within the range of low load to rated load.

[0012] Furthermore, the rotary sealing mechanism includes a sealing shoe, a sealing seat and a sealing member, which are arranged in a cavity of the inner circle of the end cover, and the sealing member is arranged between the sealing seat and the mating surface of the end cover. The sealing shoe is arranged in a cavity of the inner circle of the sealing seat, and the sealing shoe is sleeved on the rotating shaft. The gap between the inner circle of the sealing shoe and the rotating shaft is filled with sealing oil with a pressure higher than the air pressure outside the machine, forming a pressure oil film to seal the negative pressure air inside the machine.

[0013] Furthermore, the sealing oil control system includes a sealing oil tank, a sealing oil pump, an oil cooler, an oil filter, and a pressure differential valve. The sealing oil tank is connected to the gap between the inner circle of the sealing shoe and the rotating shaft through a sealing oil pipeline. The sealing oil pipeline is provided with an oil cooler, an oil filter, a pressure differential valve and a sealing oil pump; the sealing oil pump extracts the sealing oil from the sealing oil tank, and under the control of the pressure differential valve, the sealing oil with a pressure higher than the atmospheric pressure is injected into the rotating sealing mechanism in the end cover through the oil cooler and the oil filter. The sealing oil enters the gap between the sealing shoe and the rotating shaft to seal the air. The sealing oil flowing out of the end cover returns to the sealing oil tank through the pipeline and circulates again under the action of the sealing oil pump.

[0014] Furthermore, the stator frame comprises an outer skin, a ring plate, and an interface flange. Multiple ring plates are spaced axially along the outer skin. The outer skin is positioned externally and welded to the ring plates to form a hollow cylindrical structure. The stator frame is a pressure-bearing steel structure, utilizing thick outer skins and ring plates to withstand the internal and external pressure differential created by the negative pressure within the machine without deformation or damage. The stator frame utilizes a sealed structure, with airtight welds. Sealing elements are used to seal the connections between the end caps, cover plates, manholes, and other components and the frame. The frame undergoes water pressure and airtightness tests to ensure its sealing.

[0015] Furthermore, the lubricating oil system includes a lubricating oil tank, a lubricating oil pump, an oil cooler and an oil filter. The lubricating oil tank is connected to the end cover through a pipeline, and the lubricating oil pipeline is provided with a lubricating oil cooler, a lubricating oil filter and a lubricating oil pump; the lubricating oil pump extracts the lubricating oil from the lubricating oil tank, injects the lubricating oil into the bearings in the inner cavity of the end cover through the oil cooler and the oil filter to lubricate the bearings, and the lubricating oil flowing out of the bearings returns to the lubricating oil tank through the pipeline and circulates again under the action of the lubricating oil pump.

[0016] Furthermore, the cooling water system includes a cooling water tank, a cooling water pump, a water cooler and a water filter. The cooling water tank is connected to the air cooler through a pipe, and the cooling water pipe is provided with a water cooler, a water filter and a cooling water pump; the cooling water pump draws cooling water from the cooling water tank, injects it into the air cooler through the water cooler and the water filter to cool the air inside the machine, and the cooling water flowing out of the air cooler returns to the water tank through the pipe and circulates again under the action of the cooling water pump.

[0017] Furthermore, the excitation system includes an excitation transformer, an automatic voltage regulator, and a rectifier. The excitation transformer reduces the voltage of electrical energy absorbed from the external power grid and supplies it to the rectifier. Under the control of the automatic voltage regulator, the rectifier rectifies the AC power provided by the excitation transformer into DC power, which is supplied to the phase shifter shaft, thereby forming the rotating magnetic field required for phase shifter operation.

[0018] Beneficial effects of the utility model:

[0019] 1. This utility model utilizes a negative-pressure air-cooled condenser with an additional air control system. This reduces the air pressure inside the condenser to below the external atmospheric pressure when the condenser is operating at low load, creating a negative relative pressure. This reduces air friction losses and fan losses related to air density, thereby improving the efficiency and economy of the condenser during low-load operation. The air control system increases the air pressure inside the condenser as the condenser load increases, enhancing its cooling capacity and ensuring that the condenser maintains temperatures within specified limits across the entire load range from low to rated. When the condenser is operating at rated load, the air pressure inside the condenser is increased to equal the external atmospheric pressure.

[0020] 2. In the present invention, a negative pressure air-cooled phase regulator is used, and a rotary sealing mechanism is added at the contact point between the rotating shaft and the end cover. The sealing oil with a pressure higher than the atmospheric pressure is filled to perform air sealing, so as to maintain the air pressure inside the machine lower than the atmospheric pressure outside the machine.

[0021] 3. In the present invention, a negative pressure air-cooled phase shifter is used, and a sealing oil control system is added to provide sealing oil with a pressure higher than atmospheric pressure to the rotating sealing mechanism of the phase shifter, thereby preventing air with atmospheric pressure outside the machine from entering the machine and maintaining the negative pressure of the air inside the machine.

[0022] 4. In this utility model, an air-cooled phase regulator operating under negative pressure is adopted, the stator frame adopts a closed structure, the frame welds adopt airtight welds, the end covers, cover plates, manholes and other parts connected to the frame are sealed with seals, and the frame undergoes water pressure and airtightness tests to ensure the sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of the air-cooled phase regulator of the present invention.

[0024] Figure 2 This is a cross-sectional view of the air-cooled camera regulator of the present invention.

[0025] Figure 3 This is a schematic structural diagram of the rotary sealing mechanism of the air-cooled phase regulator of the present invention.

[0026] Among them, 1. Stator frame; 2. Stator unit; 3. Rotating shaft; 4. End cover; 41. Bearing; 42. Sealing shoe; 43. Sealing seat; 44. Seal; 5. Air cooler; 6. Cooling water system; 7. Sealing oil control system; 8. Lubricating oil system; 9. Air control system; 10. Excitation system. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto.

[0028] Example 1

[0029] This embodiment provides an air-cooled phase regulator operating under negative pressure, comprising a stator frame 1, a stator unit 2 and a rotating shaft 3.

[0030] The stator base 1 is a closed shell structure. The stator unit 2 is sleeved on the rotating shaft 3. The stator unit 2 is fixed inside the stator base 1. Both ends of the rotating shaft 3 extend to the outside through the stator base 1. The two ends of the rotating shaft 3 are connected to the stator base 1 through end covers 4. The end covers 4 are sealed with the stator base 1. The end covers 4 are provided with bearings 41 for supporting the rotating shaft 3 and a rotating sealing mechanism for sealing the contact between the end covers 4 and the rotating shaft 3; a cavity is provided around the stator unit 2 and the stator base 1 to form a cooling air path, and an air cooler 5 is installed on the cooling air path. The air cooler 5 is connected to a cooling water system 6. The end cover 4 is connected to a bearing lubricating oil system 8 and a sealing oil control system 7. A connecting flange is provided on the outer surface of the stator base 1, and the connecting flange is connected to an air control system 9. The output end of the rotating shaft is connected to an excitation system outside the stator base.

[0031] The air control system 9 includes a negative pressure fan, a pressure sensor, a pressure controller and a ventilation valve. The negative pressure fan is connected to the connecting flange through a gas pipeline. The stator base 1 is also connected to the ventilation valve and the pressure sensor through a pipeline. The ventilation valve and the pressure sensor are provided on the gas pipeline. The pressure controller is electrically connected to the negative pressure fan, the pressure sensor and the ventilation valve.

[0032] In this embodiment, the air friction loss and fan loss of the condenser are proportional to the density of the air within the condenser. Under a certain external atmospheric pressure, by connecting an air control system 9 to the outer surface of the stator frame 1 to reduce the air density within the condenser, these two losses can be reduced. Air density is proportional to air pressure. Lowering the air pressure within the condenser can reduce the air density within the condenser. Therefore, taking measures to lower the air pressure within the condenser can proportionally reduce the condenser's air friction loss and fan loss, significantly improving the condenser's operating efficiency and economic efficiency. By designing an air-cooled condenser operating at a certain atmospheric pressure to be below that pressure, and controlling the air pressure within the condenser to be below that pressure through a special sealing structure and air control system 9, the air friction loss and fan loss within the condenser will be lower than when operating at that atmospheric pressure. This can reduce losses during condenser operation and reduce the amount of electricity drawn from the grid, thereby improving the condenser's operating efficiency and economic efficiency.

[0033] Example 2

[0034] Compared with Example 1, the present embodiment is different in that, in the present embodiment, the rotary sealing mechanism includes a sealing shoe 42, a sealing seat 43 and a sealing member 44, the sealing shoe 42, the sealing seat 43 and the sealing member 44 are arranged in the cavity of the inner circle of the end cover 4, the sealing member 44 is provided between the sealing seat 43 and the mating surface of the end cover 4, the sealing shoe 42 is arranged in the cavity of the inner circle of the sealing seat 43, the sealing shoe 42 is sleeved on the rotating shaft 3, and the gap between the inner circle of the sealing shoe 42 and the rotating shaft 3 is filled with sealing oil with a pressure higher than that of the air outside the machine, forming a pressure oil film to seal the negative pressure air in the machine; the sealing shoe 42 is arranged in the cavity of the inner circle of the sealing seat 43, the sealing shoe 42 is sleeved on the rotating shaft 3, and the gap between the inner circle of the sealing shoe 42 and the rotating shaft 3 is filled with sealing oil with a pressure higher than that of the air outside the machine, forming a pressure oil film to seal the negative pressure air in the machine; The sealing oil control system 7 includes a sealing oil tank, a sealing oil pump, an oil cooler, an oil filter, and a pressure differential valve. The sealing oil pump tank is connected to the gap between the inner circle of the sealing shoe 42 of the rotary sealing mechanism and the rotating shaft 3 through a sealing oil pipeline. The sealing oil pipeline is provided with an oil cooler, an oil filter, a pressure differential valve and an oil tank sealing oil pump; the lubricating oil system 8 includes a lubricating oil tank, a lubricating oil pump, an oil cooler and an oil filter. The lubricating oil tank is connected to the end cover 4 through a pipeline, and the lubricating oil pipeline is provided with a lubricating oil cooler, a lubricating oil filter and a lubricating oil pump; the rest of the structure is the same as that of Example 1.

[0035] In this embodiment, the gap between the inner circle of the sealing bush 42 and the rotating shaft 3 is filled with sealing oil with a pressure higher than the air pressure outside the machine through the rotary sealing mechanism, forming a pressure oil film to seal the negative pressure air in the machine, thereby sealing the contact point between the end cover 4 and the rotating shaft 3; the sealing oil pump, under the control of the pressure differential valve, injects sealing oil of a certain pressure into the rotary sealing mechanism of the inner cavity of the end cover 4 through the sealing oil pipeline, and the sealing oil flowing out of the end cover 4 returns to the sealing oil control system 7 through the sealing oil pipeline, passes through the oil cooler, oil filter and oil tank, and then enters the rotary sealing mechanism for circulation under the action of the sealing oil pump; the lubricating oil pump injects lubricating oil into the bearing 41 in the inner cavity of the end cover 4 to lubricate the bearing 41, and the lubricating oil flowing out of the end cover 4 returns to the lubricating oil tank through the oil pipeline, passes through a series of devices such as the oil cooler and oil filter, and then enters the bearing for circulation under the action of the lubricating oil pump; thereby achieving sealing and lubrication of the end cover 4.

[0036] Example 3

[0037] Compared with Example 1, the present embodiment is different in that, in the present embodiment, the stator frame 1 includes an outer skin, a ring plate and an interface flange, a plurality of the ring plates are arranged at axial intervals along the outer skin, the outer skin is arranged outside the ring plate and welded together with the ring plate to form a hollow cylindrical structure, and a rib plate and a support tube are further provided between the outer skin and the ring plate to enhance the strength and rigidity of the stator frame 1 and ensure that the frame does not deform or damage when the air inside the machine is at negative pressure; the remaining structure is the same as that of Example 1.

[0038] In this embodiment, the stator frame 1 is a pressure-bearing steel structure with a thick outer skin and ring plates to withstand the internal and external pressure differential caused by the negative pressure of the air inside the machine without deformation or damage. The stator frame 1 adopts a sealed structure, with airtight welds. The connections between the end cap 4, cover plate, manhole, and other components and the frame are sealed with seals 44. The frame undergoes water pressure and airtightness tests to ensure its sealing. By strengthening the strength and rigidity of the stator frame 1, it is ensured that the frame will not deform or damage when the air pressure inside the machine reaches a negative pressure.

[0039] Example 4

[0040] Compared with Example 1, this embodiment differs in that the cooling water system 6 includes a cooling water tank, a cooling water pump, a water cooler and a water filter; the cooling water tank is connected to the air cooler 5 through a pipeline, and the cooling water pipeline is provided with a water cooler, a water filter and a cooling water pump; the excitation system 10 includes an excitation transformer, an automatic voltage regulator, and a rectifier; the remaining structure is the same as that of Example 1.

[0041] In this embodiment, the cooling water pump injects cooling water into the air cooler 5 to cool the air inside the machine. The cooling water flowing out of the air cooler 5 returns to the water tank through the pipeline, passes through a series of devices such as the water cooler and the water filter, and then enters the air cooler 5 for circulation under the action of the cooling water pump, thereby achieving cooling of the phase shifter; the excitation transformer reduces the voltage of the electric energy absorbed from the external power grid and provides it to the rectifier device. Under the control of the automatic voltage regulator, the rectifier device rectifies the AC power provided by the excitation transformer into DC power to supply the phase shifter shaft 3, thereby forming a rotating magnetic field of the shaft 3 required for the operation of the phase shifter.

[0042] It is understood that the present invention is described by way of certain embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. Furthermore, under the guidance of the present invention, these features and embodiments may be modified to suit specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. An air-cooled phase-shifting machine operating under negative pressure, comprising a stator frame (1), a stator unit (2) and a rotating shaft (3), characterized in that: The stator base (1) is a sealed shell structure. The stator unit (2) is sleeved on the rotating shaft (3). The stator unit (2) is fixed inside the stator base (1). Both ends of the rotating shaft (3) pass through the stator base (1) and extend to the outside. Both ends of the rotating shaft (3) are connected to the stator base (1) through end covers (4). The end covers (4) are sealed to the stator base (1). The end covers (4) are provided with bearings (41) for supporting the rotating shaft (3) and a rotating seal for sealing the contact between the end covers (4) and the rotating shaft (3). Sealing mechanism; a cavity is provided around the stator unit (2) and between the stator base (1) to form a cooling air path, an air cooler (5) is installed on the cooling air path, the air cooler (5) is connected to a cooling water system (6), the end cover (4) is connected to a bearing lubricating oil system (8) and a sealing oil control system (7), a connecting flange is provided on the outer surface of the stator base (1), the connecting flange is connected to an air control system (9), and the output end of the rotating shaft (3) is connected to an excitation system (10) outside the stator base (1).

2. The air-cooled camera according to claim 1, characterized in that: The air control system (9) includes a negative pressure blower, a pressure sensor, a pressure controller and a ventilation valve, the negative pressure blower is connected to the connecting flange through a pipeline, the stator base (1) is connected to the ventilation valve and the pressure sensor, and the pressure controller is electrically connected to the negative pressure blower, the pressure sensor and the ventilation valve.

3. The air-cooled camera according to claim 1, characterized in that: The rotary sealing mechanism comprises a sealing shoe (42), a sealing seat (43) and a sealing member (44), wherein the sealing shoe (42), the sealing seat (43) and the sealing member (44) are arranged in a cavity of an inner circle of the end cover (4), and the sealing member (44) is provided between the sealing seat (43) and the mating surface of the end cover (4). The sealing shoe (42) is arranged in a cavity of an inner circle of the sealing seat (43), and the sealing shoe (42) is sleeved on the rotating shaft (3). The gap between the inner circle of the sealing shoe (42) and the rotating shaft (3) is filled with sealing oil having a pressure higher than that of the air outside the machine.

4. The air-cooled camera according to claim 3, characterized in that: The sealing oil control system (7) comprises a sealing oil tank, a sealing oil pump, an oil cooler, an oil filter, and a pressure differential valve. The sealing oil tank is connected to the rotary sealing mechanism via a sealing oil pipeline. The sealing oil pipeline is provided with an oil cooler, an oil filter, a pressure differential valve, and a sealing oil pump.

5. The air-cooled camera according to claim 1, characterized in that: The stator frame (1) comprises an outer skin, a ring plate and an interface flange, wherein a plurality of the ring plates are arranged at axial intervals along the outer skin, the outer skin is arranged outside the ring plate and welded to the ring plate to form a hollow cylindrical structure, and a rib plate and a support pipe are further provided between the outer skin and the ring plate.

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