Synchronous phase modulation method

Abstract

To provide a synchronous condenser conversion method that can properly supply reactive power from a synchronous condenser.SOLUTION: A synchronous condenser conversion method includes a pressure regulating step in which, when converting a power generation facility of a decommissioned or idle plant to a synchronous condenser 10, the pressure of a cooling gas in a housing of a generator 1 provided in the synchronous condenser 10 is raised higher than before the conversion, and the hydraulic pressure of an oil used for the shaft seal of the generator 1 is raised higher than before the conversion. The synchronous condenser conversion method further includes a reinforcement step in which the housing is reinforced prior to the pressure regulating step, to increase the strength of the housing to a higher level than before the conversion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a synchronous phase modifier method. [Background technology]

[0002] In recent years, the introduction of renewable energy sources such as solar power, wind power, biomass power, geothermal power, and hydroelectric power has progressed. There is also a movement to decommission aging thermal and nuclear power plants. As the introduction of renewable energy progresses while the number of thermal and nuclear power plants decreases, the power grid becomes more susceptible to voltage and frequency fluctuations, as well as supply-demand imbalances and excess transmission capacity. It also becomes more susceptible to reactive power shortages.

[0003] Therefore, it has been proposed to convert the power generation equipment of decommissioned plants or idle plants into synchronous phase modifiers and supply reactive power from the synchronous phase modifiers to the power grid. For example, Patent Document 1 describes such a technology, in which "when converting hydrogen-cooled generator equipment of an idle thermal power plant into synchronous phase modifier equipment, the hydrogen gas pressure of the hydrogen-cooled generator is reduced to a predetermined pressure to operate the driving motor." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 3-82339 Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology described in Patent Document 1, when a hydrogen-cooled generator facility is converted into a synchronous phase modifier facility, the hydrogen gas pressure in the hydrogen-cooled generator is reduced, which makes it easier for the temperature of the rotor coil of the hydrogen-cooled generator to rise. This makes it necessary to suppress the excitation current of the synchronous phase modifier facility so that the rotor coil temperature does not reach a predetermined upper limit, which reduces the maximum value of reactive power that the synchronous phase modifier facility can supply. As such, the technology described in Patent Document 1 leaves room for improvement in terms of the reactive power that the synchronous phase modifier can supply.

[0006] Therefore, an object of the present invention is to provide a method for converting a synchronous phase modifier into a synchronous phase modifier, which can appropriately supply reactive power from the synchronous phase modifier. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the method for converting a power generating facility of a decommissioned plant or an idle plant into a synchronous phase modifier according to the present invention includes a pressure adjusting step of increasing the pressure of the cooling gas in the housing of the generator provided in the synchronous phase modifier to a level higher than that before the facility was converted into the synchronous phase modifier, and increasing the oil pressure of the oil used in the shaft seal of the generator to a level higher than that before the facility was converted. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a synchronous phase modifier conversion method that can appropriately supply reactive power from a synchronous phase modifier. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is an explanatory diagram showing the arrangement of equipment inside a turbine building in the synchronous phase modifier method according to the first embodiment. [Figure 2] 1 is a schematic cross-sectional view showing a cooling structure of a generator provided in a synchronous phase modifier in a synchronous phase modifier conversion method according to a first embodiment. FIG. [Figure 3] 3 is a partial enlarged view of an area P1 in FIG. 2 in the generator generator provided with the synchronous phase modifier in the synchronous phase modifier conversion method according to the first embodiment. FIG. [Figure 4]3 is a flowchart relating to a synchronous phase modifier method according to the first embodiment. [Figure 5] 10 is a flowchart relating to a synchronous phase modifier method according to a second embodiment. [Figure 6] 10 is a flowchart relating to a synchronous phase modifier method according to a third embodiment. [Figure 7] FIG. 10 is an explanatory diagram showing the arrangement of equipment near a turbine building in a first modified example of the synchronous phase modifier method according to the third embodiment. [Figure 8] FIG. 11 is an explanatory diagram showing the arrangement of equipment near a turbine building in a second modified example of the synchronous phase modifier method according to the third embodiment. [Figure 9] FIG. 10 is an explanatory diagram showing the arrangement of equipment near a turbine building in a third modified example of the synchronous phase modifier method according to the third embodiment. [Figure 10] 10 is a flowchart illustrating a synchronous phase modifier method according to a fourth embodiment. [Figure 11] FIG. 13 is an explanatory diagram showing the relationship between time zones, photovoltaic power generation amount, power transmission amount of the power grid, required reactive power, and hydrogen pressure in the synchronous phase modifier method according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Below, as an example, a case will be described in which the power generation equipment of a "decommissioned plant" is converted into a synchronous phase modifier 10 (see FIG. 1). Note that a "decommissioned plant" is a plant in which the operation and operation of the power generation equipment has ceased. Furthermore, "converting" a power generation equipment into a synchronous phase modifier 10 means using at least a part of the equipment that was previously used as a power generation equipment as the synchronous phase modifier 10. For example, cases in which certain components of the power generation equipment are replaced, added, removed, or modified, or the gas pressure or oil pressure inside the housing 13 (see FIG. 2) of the generator 1 (see FIG. 1) is changed, or the current value, voltage value, frequency, control command value, etc. are changed, are also included in the "conversion" of a power generation equipment into a synchronous phase modifier 10.

[0011] First Embodiment FIG. 1 is an explanatory diagram showing the arrangement of equipment in a turbine building 30 in a synchronous phase modifier method according to a first embodiment. First, a brief description will be given of the power generation equipment before it is converted into the synchronous phase modifier 10. The power generation equipment before it is converted into the synchronous phase modifier 10 is one that was used in, for example, a nuclear power plant or a thermal power plant. This power generation equipment has a configuration in which a high-pressure turbine 21, a low-pressure turbine 22 of a system A, a low-pressure turbine 23 of a system B, a low-pressure turbine (not shown) of a system C, and a generator 1 shown in Fig. 1 are connected in sequence via shafts.

[0012] The pressure of the steam generated by heat exchange in a nuclear reactor or the like (not shown) rotates the high-pressure turbine 21 and the low-pressure turbines of systems A, B, and C, causing the generator 1 to generate electricity. The power generated by the generator 1 is supplied to a power grid 40 via a transformer 41. The power generated by the generator 1 includes active power and reactive power. For example, a synchronous generator is used as this generator 1.

[0013] When the power generation facility is converted into a synchronous phase modifier 10, the low-pressure turbine (not shown) of system C, which is connected to the generator 1 via the shaft 5, is removed and carried out of the turbine building 30 via the large equipment entrance 31. This is because the synchronous phase modifier 10 is driven without load, and there is no particular need to connect the turbines. In addition, items that are not particularly related to the operation of the synchronous phase modifier 10 (lubrication systems, cooling systems, and condensers of each turbine: not shown) are removed as appropriate.

[0014] The construction work for converting the power generation equipment into the synchronous modifier 10 is often carried out inside the turbine building 30 in which the power generation equipment is installed, but may also be carried out outside the turbine building 30 (i.e., at the transport location). When the power generation equipment of a boiling water reactor in a nuclear power plant is converted into the synchronous modifier 10, the inside of the turbine building 30 is usually a radiation controlled area. In this case, the turbines removed from the generator 1 are not transported out until the radiation dose rate falls below a predetermined value, and are stored in the turbine building 30. A driver 3 and a drive inverter 4 are installed at the site 50 after the C-system low-pressure turbine (not shown) has been removed. That is, after the C-system low-pressure turbine (not shown) is removed from the shaft 5 of the generator 1, the driver 3 is connected to this shaft 5.

[0015] <Configuration of synchronous phase condenser> The synchronous phase modifier 10 shown in Fig. 1 is a device that supplies reactive power to a power grid 40, stabilizing the voltage of the power grid 40 and improving the power factor. The synchronous phase modifier 10 continuously changes the field current (the current of the rotor coil) to continuously change the armature current (the current of the stator coil) from a lagging phase current to a leading phase current. The synchronous phase modifier 10 also has the function of suppressing voltage disturbances caused by load fluctuations in the power grid 40 by using the inertial force (electrical and mechanical inertial force) caused by the rotation of the rotor 12 (see Fig. 2).

[0016] As shown in Fig. 1, the synchronous phase modifier 10 includes a generator 1 (also referred to as a synchronous machine), an exciter 2, a driver 3, and a drive inverter 4. The generator 1 is a synchronous machine that is driven without load. Although not shown, the generator 1 also includes a stator coil wound around a stator core and a rotor coil wound around a rotor core. The stator coil is connected to a power grid 40 via a transformer 41.

[0017] The reactive power of the synchronous phase modifier 10 is adjusted by the excitation current (DC current) supplied from the exciter 2 to the rotor coil, and this reactive power is supplied from the stator coil to the power system 40 via the transformer 41.

[0018] For example, when the synchronous phase modifier 10 is operated in a leading phase by weakening the field excitation, the rotor coil of the generator 1 functions as a reactor that absorbs a lagging phase current from the power grid 40. When the synchronous phase modifier 10 is operated in a lagging phase by strengthening the field excitation, the rotor coil of the generator 1 functions as a capacitor that absorbs a leading phase current from the power grid 40. Note that the above-described lagging phase operation is performed when the voltage drops due to load fluctuations, tide flow changes, or faults such as wire breakage in the power grid 40, resulting in a shortage of reactive power. Therefore, lagging phase operation is often performed when stabilizing the voltage of the power grid 40.

[0019] 1 is a device that supplies an excitation current to a rotor coil (not shown) of the generator 1, and is connected to the rotor coil. The exciter 2 is also connected to a control panel 81 in a central control room 80 via a generator control line 63. The reactive power of the generator 1 is adjusted by the excitation current supplied from the exciter 2 to the generator 1.

[0020] The driving machine 3 is an electric motor that accelerates the rotor 12 (see FIG. 2) of the generator 1 when starting the generator 1. That is, when starting the generator 1, the driving machine 3 accelerates the rotor 12 (see FIG. 2) of the generator 1 to a predetermined rotation speed that is synchronized with the AC frequency of the power grid 40. Note that a clutch (not shown) that switches between transmitting and interrupting power between the generator 1 and the driving machine 3 may be provided, and the clutch may interrupt the transmission of power between the generator 1 and the driving machine 3 when the rotation speed of the generator 1 reaches a predetermined value.

[0021] The drive inverter 4 is a power converter that applies a predetermined AC voltage to the drive machine 3. The input side of the drive inverter 4 is connected to a power supply panel 71 in the electrical equipment room 70 via drive machine wiring 61. The output side of the drive inverter 4 is connected to the drive machine 3 via another wiring (not shown). In addition, predetermined control signals are input to multiple switching elements (not shown) of the drive inverter 4 from a control panel 81 in the central control room 80 via drive machine control lines 62. Then, the switching elements (not shown) are switched on and off in a predetermined manner, thereby applying an AC voltage from the drive inverter 4 to the drive machine 3.

[0022] Even after the power generation facility is converted into the synchronous phase modifier 10, the central control room 80 can still be used to control and monitor the synchronous phase modifier 10. For example, an operator may route the driver control line 62 and the generator control line 63 shown in FIG. 1 to the central control room 80 and connect them to the control panel 81.

[0023] FIG. 2 is a schematic cross-sectional view showing a cooling structure of the generator 1 provided in the synchronous phase modifier. The arrows in FIG. 2 indicate the flow of hydrogen gas (cooling gas). As shown in Fig. 2, the generator 1 includes a stator 11, a rotor 12, and a housing 13. The stator 11 includes a cylindrical stator core 11a formed by laminating a plurality of electromagnetic steel plates in the axial direction, and a stator coil (not shown) wound around the stator core 11a, and is fixed inside the housing 13. The stator 11 is also provided with a predetermined cooling water flow path (not shown). The stator 11 is cooled by heat exchange with water flowing through the cooling water flow path.

[0024] The rotor 12 rotates around the central axis of the shaft 5 and is disposed rotatably radially inside the stator 11. The structure of the rotor 12 may be a so-called rotating field cylindrical shape, or may be other shapes. The rotor 12 is fixed to the shaft 5 by press-fitting or the like and rotates integrally with the shaft 5. As described above, the rotor 12 includes a rotor coil (not shown) wound around a rotor core (not shown). Note that a brush (e.g., a carbon brush) electrically connecting the rotor 12 and the exciter 2 (see FIG. 1) may be configured to slide against a slip ring (not shown) of the rotor 12.

[0025] The housing 13 is a container that contains the stator 11 and the rotor 12. As shown in FIG. 2, the housing 13 has a double structure and includes an outer housing portion 13a and an inner housing portion 13b. The outer housing portion 13a is a shell-shaped member with a cylindrical outer shape. The outer housing portion 13a is provided with a pair of holes (reference numerals not shown) for inserting the shaft 5. Although not shown in FIG. 2, a bracket 14 (see FIG. 3), a bearing portion 15 (see FIG. 3), and the like are installed inside the pair of holes.

[0026] The inner housing portion 13b is a thin-walled shell-like member that forms a flow path K1 for hydrogen gas (cooling gas) together with the outer housing portion 13a, and has a cylindrical outer shape. The inner housing portion 13b is contained within the outer housing portion 13a approximately coaxially and is fixed to the inside of the outer housing portion 13a. Similar to the outer housing portion 13a, the inner housing portion 13b is provided with a pair of holes (reference numerals not shown) for inserting the shaft 5. When the stator 11 and the rotor 12 are accommodated in the housing 13, the stator 11 and the rotor 12 are located radially inside the inner housing portion 13b.

[0027] 2, a flow path K1 through which hydrogen gas flows is provided between the outer housing portion 13a and the inner housing portion 13b. This flow path K1 may be provided over the entire circumferential area based on the central axis of the shaft 5, or may be provided over a portion of the circumferential area. A plurality of holes H1 are provided in the peripheral wall of the inner housing portion 13b to guide hydrogen gas flowing radially outward to the flow path K1.

[0028] Hydrogen gas is sealed inside the housing 13. Hydrogen gas has a fairly high thermal conductivity, which is advantageous in that it can easily cool the rotor 12 and other components. Hydrogen gas also has the property of reducing windage loss due to friction and making it less likely to cause corona discharge. Therefore, in the first embodiment, the rotor 12 and other components whose temperature has risen due to the excitation current are cooled by hydrogen gas.

[0029] As shown by the arrows in Figure 2, hydrogen gas flowing radially outward from the rotor 12 is guided to the flow path K1 through multiple holes H1 in the inner housing portion 13b. This hydrogen gas is guided via flow path K1 to areas near both ends of the rotor 12 as well as to the gap between the stator 11 and the rotor 12, and is then guided back to flow path K1 through multiple holes H1. The flow of hydrogen gas circulating within the housing 13 in this manner is formed by a centrifugal force accompanying the rotation of the rotor 12 as well as by a blower (not shown) provided inside the housing 13. Note that a cylinder (not shown) containing sealed hydrogen gas may be used as a hydrogen gas supply source, or other methods such as steam reforming or electrolysis may be used.

[0030] 2, a refrigerant flow path M1 through which a refrigerant (e.g., water) circulates is provided in the flow path K1 of the housing 13. The refrigerant flow path M1 is a flow path through which a refrigerant cooled by a cooler (not shown) circulates. The hydrogen gas, whose temperature has increased due to heat exchange with the rotor 12, is cooled by the refrigerant flowing through the refrigerant flow path M1.

[0031] FIG. 3 is a partial enlarged view of the generator 1 in an area P1 of FIG. As shown in FIG. 3, in addition to the above-described components, the generator 1 includes a bracket 14, a bearing portion 15, a shaft sealing device 16 (sealing member), a seal ring 17 (sealing member), an insulating member 18, and an airtight packing 19 (sealing member). Bracket 14 is a shell-shaped member that hydraulically suppresses leakage of hydrogen gas from housing 13 (see Figure 2). As shown in Figure 3, inside bracket 14, bearing 15, shaft sealing device 16, seal ring 17, insulating member 18, and airtight packing 19 are installed.

[0032] In the bracket 14, a pair of holes (reference numerals not shown) through which the shaft 5 is inserted are surrounded by thick oil stoppers 14a. The oil stoppers 14a are provided with grooves (reference numerals not shown) recessed radially outward from the circumferential surface of the hole through which the shaft 5 is inserted. Oil is sealed at a predetermined pressure in an oil flow path 14b, which is a gap between the groove and the circumferential surface of the shaft 5, to prevent leakage of hydrogen gas (cooling gas) from the housing 13 (see FIG. 2). The pressure of the oil sealed in the oil flow path 14b is set to balance with the pressure of the hydrogen gas sealed inside the housing 13 (see FIG. 2). The oil pressure in the oil flow path 14b is regulated to a predetermined level by a hydraulic pressure regulator (not shown).

[0033] 3 rotatably supports the shaft 5 and includes a bearing outer ring 15a and a bearing inner ring 15b. The bearing outer ring 15a is an annular member that is fixed to the inside of the bracket 14 in an electrically insulated state. The bearing inner ring 15b is an annular member that is rotatably installed radially inside the bearing outer ring 15a and rotates integrally with the shaft 5.

[0034] The shaft sealing device 16 is an annular member for preventing leakage of hydrogen gas. As shown in Fig. 3, the shaft sealing device 16 is provided around the shaft 5, axially inward of the bearing portion 15 (rotor 12 side: see Fig. 2). The shaft sealing device 16 is provided with a groove 16a recessed radially outward from its inner peripheral surface. The seal ring 17 is an annular resin member for preventing leakage of hydrogen gas, and is fitted into the groove 16a of the shaft sealing device 16. The inner peripheral surface of the seal ring 17 is in sliding contact with the peripheral surface of the shaft 5.

[0035] The insulating member 18 is a member for insulating the shaft sealing device 16 from the bracket 14, and is in the shape of a disk with a hole (not shown) in the center. The annular shaft sealing device 16 is fitted into the central hole of the insulating member 18. The airtight packing 19 is an annular resin member for sealing the gap between the insulating member 18 and the bracket 14. In addition to the oil flow path 14b, the shaft sealing device 16, the seal ring 17, and the airtight packing 19 are provided, thereby sufficiently suppressing leakage of hydrogen gas from the housing 13 (see FIG. 2). Note that FIG. 3 shows a partial enlarged view of an area P1 (see FIG. 2) on one axial side of the rotor 12 (see FIG. 2), but the other axial side of the rotor 12 has a similar configuration. Furthermore, the configuration of the generator 1 shown in FIGS. 2 and 3 is an example and is not limited to this.

[0036] <Maximum reactive power value> For example, the greater the current flowing through the rotor coil (not shown) of the generator 1 (see FIG. 2), the more heat the rotor coil generates. Therefore, to prevent the rotor coil from burning out, an upper limit temperature for the rotor coil is set in advance. Furthermore, the maximum value of the excitation current supplied to the rotor coil is determined according to the upper limit temperature of the rotor coil and the pressure of the hydrogen gas sealed in the housing 13.

[0037] For example, the higher the pressure of the hydrogen gas inside the housing 13, the denser the hydrogen gas becomes, resulting in higher cooling performance. As a result, a large excitation current can be passed through the rotor coil while maintaining the temperature of the rotor coil at or below a predetermined upper limit temperature, allowing large reactive power to be supplied from the synchronous phase modifier 10 (see FIG. 1) to the power grid 40 (see FIG. 1). In short, the higher the pressure of the hydrogen gas inside the housing 13, the greater the maximum value of reactive power that can be output from the synchronous phase modifier 10.

[0038] If power generation equipment used in a thermal power plant or a nuclear power plant were converted as is into a synchronous phase modifier 10 (see FIG. 1), the maximum value of its reactive power would be approximately the same as the maximum value of the reactive power in the power generation equipment. Therefore, in the first embodiment, when converting from a power generation equipment to the synchronous phase modifier 10 (see FIG. 1), the pressure of the hydrogen gas in the housing 13 is increased to increase the maximum value of the reactive power that can be output from the synchronous phase modifier 10.

[0039] <Decision-making process for synchronous condenser> FIG. 4 is a flowchart relating to the synchronous phase modifier method (also see FIGS. 1 and 2 as appropriate). The series of processes shown in FIG. 4 is a decision process made by a person such as a manager or worker (referred to as a manager, etc.) when converting a power generating facility into a synchronous phase modifier 10. In step S101, the manager or the like determines the amount of increase in the pressure of the hydrogen gas. That is, the manager or the like determines the amount of increase in the hydrogen gas in the housing 13 of the generator 1, based on the amount of increase in the hydrogen gas before conversion to the synchronous phase modifier 10 (when the power generation equipment is in use).

[0040] As described above, the higher the pressure of the hydrogen gas inside the housing 13, the higher the density of the hydrogen gas, and therefore the greater the amount of heat dissipated (cooling amount) per unit time from the rotor 12. The administrator or the like determines the amount of increase in the hydrogen gas pressure so that the rotor coil does not exceed the upper limit temperature when the excitation current of the generator 1 reaches a predetermined maximum value (corresponding to the maximum reactive power).

[0041] If the hydrogen gas supply capacity of the existing power generation facility is insufficient, the administrator or the like may modify the hydrogen gas supply source (not shown) as appropriate so that the increased amount of hydrogen gas (S101) is met. Alternatively, for example, the flow rate of the refrigerant circulating through the refrigerant flow path M1 (see FIG. 2) (the rotation speed of the refrigerant pump: not shown) may be increased, or the capacity of the cooler (not shown) that cools the refrigerant may be increased. These methods also allow the amount of heat dissipated per unit time by the rotor 12 to be increased.

[0042] Next, in step S102, the manager or the like determines the hydraulic pressure for the shaft seal. That is, the manager or the like determines the hydraulic pressure of the oil flow path 14b (see FIG. 3) to prevent hydrogen gas from leaking from the housing 13 of the generator 1. As described above, the hydraulic pressure of the oil flow path 14b is set to balance with the pressure of the hydrogen gas inside the housing 13. That is, the higher the pressure of the hydrogen gas inside the housing 13 (the value after the pressure increase in S101), the higher the hydraulic pressure for sealing the hydrogen gas. Therefore, in step S102, the manager or the like determines the hydraulic pressure for the shaft seal according to the pressure of the hydrogen gas (the value after the pressure increase in S101).

[0043] If the hydraulic pressure supply capacity of an existing power generation facility is insufficient, the hydraulic pressure adjusting device (not shown) may be modified appropriately so that the specified hydraulic pressure (S102) can be supplied. Furthermore, the "sealing members" such as the shaft sealing device 16 (see FIG. 3), the seal ring 17 (see FIG. 3), and the airtight packing 19 (see FIG. 3) may be modified or replaced to use those with higher hydrogen gas sealing performance. Additionally, for example, the bracket 14 (see FIG. 3) may be modified or replaced to use an oil stopper 14a (see FIG. 3) with a thicker wall thickness than before conversion to the synchronous phase modifier 10.

[0044] In step S103, the manager or the like determines whether reinforcement of the housing 13 is necessary. That is, the manager or the like determines whether reinforcement of the housing 13 is necessary so that damage to the surrounding area can be minimized even if hydrogen inside the housing 13 is burned. Note that even in the power generation facility before conversion to the synchronous phase modifier 10, the housing 13 is designed to have sufficient strength in preparation for the combustion of hydrogen gas, which is a flammable gas. However, if the pressure of the hydrogen gas is increased (S101), there is a high possibility that the pressure generated when the hydrogen gas is burned will increase. Therefore, the manager or the like estimates the pressure generated when hydrogen gas is burned and reinforces the housing 13 as necessary. When reinforcing the housing 13, for example, construction work such as installing ribs (not shown) on the housing 13 or making the housing 13 a multi-layer structure is performed.

[0045] Next, in step S104, the manager or the like determines whether or not modification of the brushes (not shown) is necessary. That is, the manager or the like determines whether or not modification is necessary, such as increasing the number of brushes or replacing them with brushes of different specifications, based on the current capacity (allowable current value) per brush (e.g., carbon brush) used to supply excitation current from the exciter 2 to the generator 1.

[0046] For example, if the brushes (not shown) used before conversion to the synchronous phase modifier 10 are used as they are, the current flowing through the brushes may exceed a predetermined allowable value depending on the magnitude of the excitation current, causing the brushes to become too hot. In such cases, the administrator or the like can make modifications such as increasing the number of brushes or changing the brushes to ones with a larger current capacity than the current brushes, thereby suppressing the current flowing through the brushes to within the predetermined allowable value.

[0047] After the processing of steps S101 to S104 (a decision-making process by an administrator or the like) is performed, work associated with converting the power generation facility into a synchronous phase modifier 10 is carried out on-site. Specifically, when converting the power generation facility of a decommissioned plant (or an idle plant) into a synchronous phase modifier 10, the work includes a "pressure adjustment process" (corresponding to S101 and S102 in FIG. 4) in which the pressure of the hydrogen gas (cooling gas) in the housing 13 of the generator 1 provided in the synchronous phase modifier 10 is made higher than before the conversion into the synchronous phase modifier 10, and the oil pressure of the oil used in the shaft seal of the generator 1 is made higher than before the conversion.

[0048] In the "pressure adjustment process", the increase in the hydrogen gas pressure and the increase in the oil pressure may be performed in any order, or may be performed in parallel. The amount of increase in the hydrogen gas (cooling gas) pressure based on the pressure before conversion (before conversion from the power generation facility to the synchronous phase modifier 10) is set based on the maximum value of the reactive power that can be output by the synchronous phase modifier 10.

[0049] Furthermore, prior to the above-mentioned "pressure adjustment step," a "reinforcement step" (corresponding to S103 in FIG. 4) may be further included in which the housing 13 is reinforced to make the strength of the housing 13 higher than that before conversion (before conversion from power generation equipment to the synchronous phase modifier 10). This makes it possible to fully prepare for the combustion of hydrogen gas even when the pressure of hydrogen gas inside the housing 13 is increased.

[0050] Furthermore, prior to the above-mentioned "voltage adjustment step," a "brush modification step" (corresponding to S104 in FIG. 4) may be further included in which the current capacity per brush (not shown) electrically connecting the generator 1 and the exciter 2 is increased compared to before conversion (before conversion from the power generation facility to the synchronous phase modifier 10), or the number of brushes is increased compared to before conversion. This makes it possible to suppress the current flowing through the brushes to a predetermined allowable value or less.

[0051] Furthermore, prior to the above-mentioned "pressure adjustment process," a "sealing member strengthening process" may be further included in which the performance of the "sealing member" that seals the hydrogen gas (cooling gas) in the housing 13 is improved compared to before conversion (before conversion from the power generation equipment to the synchronous phase modifier 10). The "sealing member" includes the shaft sealing device 16 (see FIG. 3), the seal ring 17 (see FIG. 3), the airtight packing 19 (see FIG. 3), etc.

[0052] The order of the "reinforcement process," "brush modification process," and "sealing member strengthening process" described above is not particularly limited and can be changed as appropriate. For example, the "reinforcement process" or the "sealing member strengthening process" may be performed before the "brush modification process," or the "reinforcement process" or the "sealing member strengthening process" may be performed after the "brush modification process." In addition, for example, the "reinforcement process" or the "brush modification process" may be performed before the "sealing member strengthening process," or the "reinforcement process" or the "brush modification process" may be performed after the "sealing member strengthening process."

[0053] Furthermore, after the above-described "pressure adjusting step" or before the "pressure adjusting step", the method may further include a "flow rate increasing step" of increasing the flow rate of the refrigerant that exchanges heat with the hydrogen gas (cooling gas) in the housing 13 compared to before the conversion (before the conversion from the power generation facility to the synchronous phase modifier 10). This promotes cooling of the hydrogen gas, thereby promoting cooling of the rotor coil (not shown) by the hydrogen gas. Note that the "flow rate increasing step" is performed after the above-described "reinforcement step", "brush modification step", and "sealing member strengthening step".

[0054] After the work associated with converting the power generation equipment into the synchronous phase modifier 10 is completed, operation of the synchronous phase modifier 10 is started based on a command signal from a central control room 80 (see FIG. 1). Information regarding a malfunction in the power system 40 (see FIG. 1) is transmitted to the central control room 80 (see FIG. 1) via, for example, a central load dispatching center (not shown) or local control centers (not shown). Then, the reactive power output from the synchronous phase modifier 10 is appropriately adjusted by the excitation current supplied from the exciter 2.

[0055] In consideration of cybersecurity, operation commands from a central load dispatching center (not shown) may be transmitted via a dedicated line (not shown), or a predetermined firewall may be provided. Also, the synchronous phase modifier 10 may be configured to be controlled from a remote location.

[0056] According to the first embodiment, when converting a power generation facility into a synchronous phase modifier 10, the maximum value of reactive power that can be output from the synchronous phase modifier 10 can be increased by increasing the pressure of the hydrogen gas sealed in the housing 13 (see FIG. 2). Therefore, when a predetermined amount of reactive power is required, the number of bases required when converting (converting) a power generation facility into a synchronous phase modifier 10 can be reduced. This reduces the cost required for conversion to a synchronous phase modifier 10, making it possible to lower the unit cost of generating reactive power, which in turn contributes to society.

[0057] Second Embodiment The second embodiment differs from the first embodiment in that, prior to determining the amount of increase in the pressure of the hydrogen gas, an administrator or the like estimates the required amount of reactive power per synchronous phase modifier 10 (see FIG. 1). Note that other points (such as the configuration of the synchronous phase modifier 10, see FIGS. 1 to 3) are the same as those of the first embodiment. Therefore, only the parts that differ from the first embodiment will be described, and a description of the overlapping parts will be omitted.

[0058] FIG. 5 is a flowchart of the synchronous phase modifier method according to the second embodiment (also see FIG. 1 as needed). The series of processes shown in FIG. 5 is a process of estimation and decision made by a manager or the like when converting a power generation facility into a synchronous phase modifier 10. In step S201, the manager or the like estimates the required amount of reactive power that should be supplied by each synchronous phase modifier 10. When estimating the required amount of reactive power, the status of the domestic power system, the reactive power (total amount) that will be required if a malfunction occurs in the power system 40 in the area surrounding the synchronous phase modifier 10, the number of power generation facilities that can be diverted to the synchronous phase modifier 10, etc. are taken into consideration.

[0059] The processing of steps S202 to S205 in Fig. 5 is the same as steps S101 to S104 (see Fig. 4) in the first embodiment, in this order, and therefore description thereof will be omitted. Note that in step S202, first, the maximum value of reactive power that can be output by the synchronous phase modifier 10 is calculated based on the required amount of reactive power estimated in step S201. Then, the amount of increase in pressure of the hydrogen gas is determined so that the temperature of the rotor 12 (see Fig. 2) will be equal to or lower than a predetermined upper limit temperature even when the maximum amount of reactive power is output.

[0060] Furthermore, when converting from a power generation facility to the synchronous phase modifier 10, the power transmission voltage control performed on the high-voltage side of the transformer 41 (see FIG. 1) of the power generation facility may be changed to a PSVR (Power System Voltage Regulator) based on the excitation control of the generator 1 (see FIG. 1).

[0061] According to the second embodiment, the amount of increase in the pressure of the hydrogen gas is determined based on the required amount of reactive power per synchronous phase modifier 10 (S201, S202 in FIG. 5). This makes it possible to prevent the pressure of the hydrogen gas in the housing 13 (see FIG. 2) from being set unnecessarily high, and ultimately to suppress windage loss in the generator 1.

[0062] Third Embodiment The third embodiment differs from the first embodiment in that when converting a power generation facility into a synchronous phase modifier 10 (see FIG. 1), the control panel 81 (control device: see FIG. 1) is modified and the control method is changed. Note that other aspects (such as the configuration of the synchronous phase modifier 10, see FIGS. 1 to 3) are the same as those of the first embodiment. Therefore, only the parts that differ from the first embodiment will be described, and a description of the overlapping parts will be omitted.

[0063] FIG. 6 is a flowchart relating to the synchronous phase modifier method according to the third embodiment (also refer to FIG. 1 as appropriate). The series of processing steps shown in FIG. 6 is a decision process made by an administrator or the like when converting a power generation facility into a synchronous phase modifier 10. 6 are the same as steps S101 to S104 (see FIG. 4) in the first embodiment, and therefore will not be described again. After determining in step S304 whether or not the brush (not shown) needs to be modified, the manager or the like performs the process of step S305. That is, in step S305, the manager or the like determines whether or not the control panel 81 (see FIG. 1) needs to be modified or the control method needs to be changed.

[0064] For example, in excitation control for stabilizing the power system 40 (see FIG. 1), it is desirable to detect the effective power, power oscillation frequency, and also the rotational speed of the generator 1 with high accuracy and high speed. Furthermore, it is desirable to use a control algorithm that can suppress power oscillations based on this data (input signals to the control panel 81). A digital automatic voltage regulator (D-AVR) may be used as a device suitable for such a control algorithm. For example, if the power generation equipment before conversion to the synchronous phase modifier 10 was an analog control type automatic voltage regulator, it may be modified (or replaced) with a digital automatic voltage regulator as necessary.

[0065] As will be explained in the first, second and third modified examples (FIGS. 7, 8 and 9) below, the layout of the control panel 81 can be changed as appropriate.

[0066] <First Modification> FIG. 7 is an explanatory diagram showing the arrangement of equipment near the turbine building 30 in a first modified example of the third embodiment. In the example of Fig. 7, a control room 80A is provided adjacent to the outside of the turbine building 30. A control panel 81 provided in the control room 80A is connected to the exciter 2 via a generator control line 63, and is also connected to the drive inverter 4 via a drive control line 62. Based on a control signal from the control panel 81, the excitation current of the exciter 2 is changed, and the reactive power of the synchronous phase modifier 10 is adjusted.

[0067] If the power generation facility before conversion into the synchronous phase modifier 10 is a nuclear power plant, the inside of the turbine building 30 is often a radiation controlled area for a predetermined period of time after decommissioning. In such a case, if the control room 80A adjacent to the outside of the turbine building 30 is outside the radiation controlled area, the procedures for workers entering and exiting the control room 80A can be simplified.

[0068] <Second Modification> FIG. 8 is an explanatory diagram showing the arrangement of equipment near the turbine building 30 in a second modified example of the third embodiment. In the example of Fig. 8, a new control room 80B is provided adjacent to the inside wall of the turbine building 30. For example, if there is no extra space outside the turbine building 30, the control room 80B may be provided inside the turbine building 30, as shown in Fig. 8. Even in this case, the exciter 2 and the drive inverter 4 can be controlled in a predetermined manner based on control signals from the control panel 81, as in the case of Fig. 7.

[0069] <Third Modification> FIG. 9 is an explanatory diagram showing the arrangement of equipment near the turbine building 30 in a third modified example of the third embodiment. As shown in Fig. 9, a control room may not be provided, and a control panel 81 may be provided inside the turbine building 30. Even in this case, the exciter 2 and the drive inverter 4 can be controlled in a predetermined manner by the control panel 81, as in the first and second modified examples.

[0070] Fourth Embodiment The fourth embodiment differs from the first embodiment in that a manager or the like selects a generator 1 to be converted into a synchronous phase modifier 10 based on operational needs as well as the control width and control speed of reactive power. Note that other points (such as the configuration of the synchronous phase modifier 10, see FIGS. 1 to 3) are the same as those of the first embodiment. Therefore, only the parts that differ from the first embodiment will be described, and a description of overlapping parts will be omitted.

[0071] FIG. 10 is a flowchart relating to the synchronous phase modifier method according to the fourth embodiment (also refer to FIG. 1 as appropriate). The series of processing steps shown in FIG. 10 is a decision process made by a manager or the like when converting a power generation facility into a synchronous phase modifier 10. For example, at a site (power plant) where multiple power plants are installed, the capacity and excitation method often differ for each power plant before conversion to a synchronous phase modifier 10. Furthermore, at a given power plant, the capacity and excitation method may differ for each generator 1. Therefore, in the fourth embodiment, the manager or the like estimates the number of generators 1 to be converted to synchronous phase modifiers 10 based on system analysis, taking into account the location conditions and the amount of reactive power required, and selects the generators 1 to be converted.

[0072] In step S401, the manager or the like selects units (generators 1) to be retrofitted to synchronous phase modifiers 10. Specifically, the manager or the like estimates the number of units (number of generators 1) that require retrofitting based on a predetermined system analysis, and further selects the generators 1 to be converted (remodeled) to synchronous phase modifiers 10, taking into consideration the reactive power control width and control speed as well as operational needs. At this time, it is desirable for the manager or the like to also consider the increase in reactive power (the increase per unit based on the amount before conversion to synchronous phase modifier 10). Note that steps S402 to S405 in FIG. 10 are the same as steps S101 to S104 (see FIG. 4) in the first embodiment in this order, and therefore a description thereof will be omitted.

[0073] According to the fourth embodiment, the generator 1 to be retrofitted with the synchronous phase modifier 10 is selected based on operational needs as well as the control width and control speed of reactive power. This allows the synchronous phase modifier 10 to appropriately supply reactive power to the power system 40, thereby stabilizing the power system 40.

[0074] Fifth Embodiment The fifth embodiment differs from the first embodiment in that maintenance and inspection of the generator 1 is performed based on the operating history of the generator 1 before it is converted into a synchronous phase modifier 10 (see FIG. 1). Note that other points (such as the configuration of the synchronous phase modifier 10, see FIGS. 1 to 3) are the same as those of the first embodiment. Therefore, only the parts that differ from the first embodiment will be described, and a description of the overlapping parts will be omitted.

[0075] The fifth embodiment will be described with reference to FIG. Typically, maintenance and inspection of a generator 1 involves replacing consumable parts such as seals approximately once every five years, and major work such as coil rewinding is performed approximately once during the product's lifespan. Furthermore, during shutdown and storage of the generator 1, consideration is given to rust, deterioration of resin materials, and malfunctions of rotating machines such as the generator 1. Specifically, maintenance using volatile rust inhibitors, the use of so-called dry storage and water-filled storage, and periodic turning of rotating machines (to eliminate turbine rotor deflection) are performed. In other words, each generator 1 often has a different operating history and storage history. Therefore, when converting a power generation facility into a synchronous phase modifier 10, it is desirable to perform appropriate maintenance and inspections taking into account the operating history and storage history of the generator 1.

[0076] For example, if the generator 1 was in use until immediately before conversion to the synchronous phase modifier 10, it is desirable to perform maintenance and inspection of the generator 1 as an extension of the maintenance and inspection plan that had been in place up to that point. However, if the generator 1 reaches the end of its product life and is decommissioned, the administrator etc. should also consider whether or not the generator 1 can be used as the synchronous phase modifier 10.

[0077] Furthermore, when converting power generation equipment that has not been used for a long period of time (for example, several years) into a synchronous phase modifier 10, it is desirable to take into consideration the state of the equipment while it is out of service. For example, for a generator 1 that has been continuously maintained in anticipation of restarting operation, it is desirable to perform maintenance inspections as an extension of that maintenance. The manager or the like should then perform an open inspection of the generator 1 (inspection of the inside of the generator 1) in conjunction with the construction work for converting the equipment into a synchronous phase modifier 10.

[0078] Furthermore, in the case of a generator 1 that has been stored without any particular maintenance in anticipation of decommissioning a nuclear power plant or the like, it is desirable to perform a predetermined operational test in addition to an overhaul inspection and replacement of consumable parts. For example, prior to the construction work to convert the generator 1 into a synchronous phase modifier 10, an open inspection of the generator 1 and an inspection of the associated systems may be performed. Based on the inspection results, the manager or the like considers whether or not large-scale construction work such as coil rewinding is necessary. Since large-scale construction work can take years from planning to completion, it is desirable to inspect the generator 1 early in the planning process for converting the generator 1 into a synchronous phase modifier 10. Furthermore, when rewinding the coil of the generator 1, the manager or the like may consider the reactive power output and adopt a winding method that can mitigate the effects of heat generation at the turn-back end, which is particularly susceptible to overheating.

[0079] According to the fifth embodiment, when the generator 1 is converted into the synchronous phase modifier 10, inspection is performed taking into consideration the operation history of the generator 1, and therefore the reliability of the synchronous phase modifier 10 can be improved.

[0080] Sixth Embodiment The sixth embodiment differs from the first embodiment in that when power generation equipment of a nuclear power plant is converted into a synchronous phase modifier 10, air-cooling is used for cooling the power supply system. Note that other points (such as the configuration of the synchronous phase modifier 10, see FIGS. 1 to 3) are the same as those of the first embodiment. Therefore, only the parts that differ from the first embodiment will be described, and a description of the overlapping parts will be omitted.

[0081] The sixth embodiment will also be described with reference to FIG. When a nuclear power plant is decommissioned and its power generation equipment is converted to a synchronous phase modifier 10, the capacity of the nuclear power plant's cooling equipment (not shown) is often reduced or replaced along with the removal of the reactor body (not shown). Specifically, the capacity of the cooling equipment is reduced or replaced in response to the magnitude of the thermal load of the synchronous phase modifier 10, and in this case, it is desirable to use air-cooled cooling equipment rather than seawater-based cooling equipment. This is because seawater-based cooling equipment requires a very large installation space and is expensive to install. Air-cooled cooling equipment has the advantage of being versatile and can be used even in areas not adjacent to the sea. It is also desirable to promote the use of air-cooled cooling equipment for power supply systems.

[0082] Regarding the arrangement of the equipment in the turbine building 30, the central control room 80 may be removed, and a control panel 81 for the synchronous phase modifier 10 may be arranged inside or outside the turbine building 30 (in a non-radiation controlled area), as shown in Figs. 7 to 9. It is also desirable to carry out equipment that is not particularly necessary for the operation of the synchronous phase modifier 10 to a non-controlled area near the turbine building 30 so that it can be disposed of later. This allows the work related to the decommissioning of the nuclear power plant to proceed smoothly.

[0083] According to the sixth embodiment, when converting a power generation facility into a synchronous phase modifier 10, equipment costs can be reduced by promoting air-cooling of cooling equipment (not shown). Furthermore, by carrying out equipment that is not particularly necessary for the operation of the synchronous phase modifier 10 to a non-controlled area, work related to the decommissioning of the nuclear power plant can be carried out smoothly.

[0084] Seventh Embodiment The seventh embodiment differs from the first embodiment in that the pressure of hydrogen gas in the housing 13 (see FIG. 2) is changed based on the amount of reactive power required. Note that other aspects (such as the configuration of the synchronous phase modifier 10, see FIGS. 1 to 3) are similar to those of the first embodiment. Therefore, only the parts that differ from the first embodiment will be described, and a description of the overlapping parts will be omitted.

[0085] FIG. 11 is an explanatory diagram showing the relationship between time zones, photovoltaic power generation amount, power transmission amount of the power grid, required reactive power, and hydrogen pressure (also see FIGS. 1 and 2 as appropriate). Note that the "hydrogen pressure" in the table of FIG. 11 refers to the pressure of the hydrogen gas sealed in the housing 13 of the generator 1 (see FIG. 2). For example, in Japan, the amount of solar power generation (total amount of generated power) is increasing, particularly in the Kyushu region. Therefore, during the daytime when solar power generation is performed, the amount of power generated in the Kyushu region is high, and the power generated there is transmitted to large-scale demand areas such as the Kansai region. By converting power generation equipment such as nuclear power plants and thermal power plants included in the power transmission route into synchronous phase modifiers 10 and supplying reactive power, it is possible to contribute to the stabilization of the power grid 40.

[0086] As shown in Fig. 11, during daytime hours (e.g., 7:00 to 17:00), the amount of solar power generation per unit time and the amount of power transmitted by the power grid 40 (see Fig. 1) are large, and therefore the amount of reactive power required is also large. Also, during nighttime hours (e.g., 17:00 to 7:00), the amount of solar power generation per unit time and the amount of power transmitted by the power grid 40 (see Fig. 1) are small, and therefore the amount of reactive power required is also small. Therefore, in the seventh embodiment, the generator 1 (see Fig. 2) provided in the synchronous phase modifier 10 (see Fig. 1) is configured so that the pressure setting of the hydrogen gas in the housing 13 (see Fig. 2) can be changed.

[0087] Specifically, as shown in FIG. 11, the pressure of the hydrogen gas (cooling gas) in the housing 13 (see FIG. 2) is set higher during the daytime than at night. In other words, the pressure of the hydrogen gas in the housing 13 is set higher during the daytime when the demand for reactive power in the power grid 40 (see FIG. 1) is high than during the nighttime when the demand for reactive power is low. This setting of the hydrogen gas pressure is performed after the "pressure adjustment process" of increasing the pressure of the hydrogen gas when diverting it to the synchronous phase modifier 10 (see FIG. 1), while the synchronous phase modifier 10 is in operation. The demand for reactive power in the power grid 40 is, for example, the reactive power (amount of reactive power per unit time) requested of the synchronous phase modifier 10 by a central load dispatching center (not shown).

[0088] As described above, the higher the pressure of the hydrogen gas inside the housing 13 (see FIG. 2), the higher the cooling performance of the rotor 12 (see FIG. 2). Therefore, when a large amount of reactive power is output from the synchronous phase modifier 10, the temperature of the rotor coil (not shown) can be kept below a predetermined upper limit temperature by increasing the pressure of the hydrogen gas. This allows the synchronous phase modifier 10 to appropriately supply reactive power to the power grid 40 even during daytime hours when a relatively large amount of reactive power is required. The pressure of the hydrogen gas inside the housing 13 may be adjusted by the control panel 81 (see FIG. 1) or manually.

[0089] Alternatively, historical data showing the transition of the required value of reactive power in each time period may be acquired in advance, and the pressure of hydrogen gas in the housing 13 may be set higher as the required value of reactive power increases.

[0090] According to the seventh embodiment, the maximum value of reactive power that can be output from the synchronous phase modifier 10 can be adjusted by increasing the pressure of hydrogen gas in the housing 13 (see FIG. 2) during the daytime and decreasing the pressure of hydrogen gas during the nighttime. Therefore, for example, the pressure of hydrogen gas in the housing 13 can be decreased during the nighttime when the amount of required reactive power is relatively small, thereby reducing windage loss of the generator 1 (see FIG. 2) and achieving high efficiency.

[0091] <<Variations>> Although the synchronous phase modifier method according to the present invention has been described in each embodiment, the present invention is not limited to these descriptions and various modifications can be made. For example, in each embodiment, a case has been described in which the power generation equipment of an "abandoned plant" is converted into the synchronous phase modifier 10, but this is not limiting. For example, each embodiment can also be applied to a case in which the power generation equipment of an "idle plant" is converted into the synchronous phase modifier 10. Note that an "idle plant" is a plant in which the power generation equipment remains unused.

[0092] In addition, in each embodiment, the synchronous phase modifier 10 (see FIG. 1) is provided with the driving machine 3 (see FIG. 1), but this is not limiting. For example, the driving machine 3 may be omitted, and the generator 1 may be started using a thyristor rectifier or the like (not shown).

[0093] In addition, in each embodiment, the case where hydrogen gas is used as the cooling gas sealed in the housing 13 (see FIG. 2) has been described, but other gases (e.g., air) may also be used. In this case, the cooling gas may be either a flammable gas or a non-flammable gas. Furthermore, in each embodiment, the case where water is used as the refrigerant that exchanges heat with the hydrogen gas inside the housing 13 has been described, but other types of refrigerant may also be used.

[0094] Furthermore, in the seventh embodiment, the hydrogen gas pressure in the housing 13 (see FIG. 2) is increased during the daytime and decreased during the nighttime, but this is not limiting. For example, the control panel 81 (see FIG. 1) may change the hydrogen gas pressure in the housing 13 based on the amount of reactive power momentarily requested from the synchronous phase modifier 10 by a central load dispatching center or the like (not shown). In other words, after the "pressure adjustment process," during operation of the synchronous phase modifier 10 (see FIG. 1), the set pressure value of the hydrogen gas (cooling gas) in the housing 13 (see FIG. 2) may be changed based on the amount of reactive power requested in the power grid 40 (see FIG. 1). For example, the set pressure value of the hydrogen gas (cooling gas) in the housing 13 may be set to a higher value as the amount of reactive power requested in the power grid 40 increases. This eliminates the need to set the hydrogen gas pressure unnecessarily high, thereby reducing windage loss in the generator 1 and improving efficiency.

[0095] Furthermore, the embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the configurations described. Furthermore, some of the configurations of the embodiments may be added to, deleted from, or replaced with other configurations. Furthermore, the mechanisms and configurations described above are those that are considered necessary for the explanation, and do not necessarily represent all mechanisms and configurations of the product. [Explanation of symbols]

[0096] 1. Generator 2 Exciter 3 Drive unit 4. Drive inverter 5 shaft 10 Synchronous phase modifier 11 Stator 12 rotor 13. Housing 14 Bracket 15 Bearing section 16 Shaft sealing device (sealing member) 17 Seal ring (sealing component) 18 Insulating material 19 Airtight packing (sealing material) 40 Power system

Claims

1. A method for converting a power generation facility of a decommissioned or idle plant into a synchronous phase condenser, comprising a pressure adjusting step of increasing the pressure of a cooling gas in a housing of a generator provided in the synchronous phase condenser to a level higher than that before the facility was converted into the synchronous phase condenser, and increasing the oil pressure of oil used in a shaft seal of the generator to a level higher than that before the facility was converted.

2. the cooling gas is a flammable gas, The method further includes a reinforcing step of reinforcing the housing prior to the pressure adjusting step to increase the strength of the housing compared to before the conversion.

2. The method for converting a synchronous phase modifier according to claim 1,

3. The method further includes, prior to the voltage adjustment step, a brush modification step of increasing the current capacity per brush electrically connecting the generator and the exciter compared to before the conversion, or increasing the number of the brushes compared to before the conversion.

2. The method for converting a synchronous phase modifier according to claim 1,

4. The amount of increase in the pressure of the cooling gas in the housing from the reference value before the conversion is set based on the maximum value of reactive power that can be output by the synchronous phase modifier.

2. The method for converting a synchronous phase modifier according to claim 1,

5. The method further includes a flow rate increasing step of increasing the flow rate of the refrigerant that exchanges heat with the cooling gas in the housing after the pressure adjusting step or before the pressure adjusting step, compared to before the diversion.

2. The method for converting a synchronous phase modifier according to claim 1,

6. The method further includes a sealing member strengthening step of enhancing the performance of the sealing member that seals the cooling gas in the housing, prior to the pressure adjusting step, compared to before the conversion.

2. The method for converting a synchronous phase modifier according to claim 1,

7. After the pressure adjusting step, during operation of the synchronous phase modifier, the pressure of the cooling gas in the housing is set higher in a time period when the demand for reactive power in the power system is high than in a time period when the demand for reactive power in the power system is low. The synchronous phase modifier method according to any one of claims 1 to 6,

8. After the pressure adjusting step, during operation of the synchronous phase modifier, the pressure of the cooling gas in the housing is set higher during the daytime than at night. The synchronous phase modifier method according to any one of claims 1 to 6,

9. After the pressure adjusting step, during operation of the synchronous phase modifier, a pressure setting value of the cooling gas in the housing is changed based on a demand for reactive power in the power system. The synchronous phase modifier method according to any one of claims 1 to 6,

10. The greater the reactive power demand in the power system, the higher the pressure setting value of the cooling gas in the housing is set. The method for converting a phase modifier into a synchronous modifier according to claim 9,

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