JPH02101943A - Cooling apparatus for turbo-generator - Google Patents

Abstract

PURPOSE:To prevent an explosion by catching fire by releasing hydrogen in the air and by supplying N2 gas when the concentration of hydrogen generated in the tank of cooling water circulating in a generator to be cooled by hydrogen and cooling said hydrogen exceeds a specified value. CONSTITUTION:The inside of a stator winding 2 provided in a generator 1 to be cooled by hydrogen gas is made hollow and cooling water is caused to circulate there. Cooling water goes from reservoir 3 via pump 4, cooler 5, feed water pipe 6, inlet header 7, insulating tube 8, stator winding 2, insulating tube 9, outlet header 10 and return pipe 11 and returns to said reservoir 3. The gas pressure of hydrogen is made larger than the water pressure of cooling water to prevent said cooling water from jetting. Hydrogen gas mixed with cooling water in operation is separated in said reservoir 3. The separated gas is sucked up by a pump 15 and the concentration of hydrogen is detected by detector 13 and monitor 14, and when said concentration exceeds a specified value, an automatic switching valve 16 and N2 gas supply valve 19 are switched to release hydrogen gas into an atmospheric escape pipe 12 and to supply N2 gas from tank 21. Thus, it is possible to prevent an explosion by catching fire.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a cooling system for a hydrogen-cooled turbine generator, and in particular, the present invention relates to a cooling system for a hydrogen-cooled turbine generator, and in particular, to prevent abnormalities in the in-machine cooling water system that directly cools the stator windings with water. This invention relates to an improvement in a cooling system that has the ability to immediately detect hydrogen gas that enters the cooling water system and safely discharge it into the atmosphere.

(Prior Art) Generally, in a large-capacity turbine generator, a rotor winding conductor is cooled with hydrogen gas, a stator winding conductor has a hollow structure, and the inside of this conductor is cooled with high-purity cooling water. For example, as shown in the schematic system diagram in Figure 3, hydrogen gas is sealed inside the turbine generator l, and the stator windings inside the
is composed of a hollow conductor. It is connected to a water storage tank 3 via a pipe connected to one end of the stator winding 2 via an outlet header 10. A water supply pipe 6 is installed between this water storage tank 3 and an inlet header 7 connected to the other end of the stator winding 2 via an insulated pipe 8, and a pump is installed in the middle of this water supply pipe 6. 4 and a cooler 5 are provided. A return pipe 11 is provided between the outlet header 10 and the water tank 2. The upper part of the water storage tank 3 is connected to an atmosphere discharge pipe 12.

In such a configuration, cooling water stored in the water tank 3 by operating the pump 4 is introduced into the turbine generator 1 through the water supply pipe 6 via the cooler 5, and is introduced into the turbine generator 1 through the inlet header 7. and is supplied to the stator winding 2 via the insulating tube 8. By cooling the stator winding 2, the high temperature cooling water is similarly circulated to the water storage tank 3 via the insulating pipe 9, the outlet header 10 and the return pipe 11.

In such a system, during operation of the turbine generator 1, the internal hydrogen gas pressure is maintained higher than the water pressure inside the conductor of the stator winding 2. Therefore, if minute cracks occur in the circulation path inside the machine, for example in the many silver brazed parts of the internal conductor of the stator winding 2, the cooling water will flow from there. Instead of blowing out, hydrogen gas will enter the cooling water.

For this reason, the hydrogen gas is separated from the cooling water in the water storage tank 3, and further led to the atmosphere discharge pipe 12 and discharged into the atmosphere.

(Problems to be Solved by the Invention) Conventionally, serious abnormal accidents such as the occurrence of cracks in the cooling water system in the turbine generator 1 as shown in FIG. Based on the increased consumption of hydrogen gas in the cooling water system, we are trying to find cracks in the cooling water system.

However, this method does not directly detect the occurrence of cracks, and the causes of increased hydrogen gas consumption include defects in the hydrogen gas shaft seals at both wheel ends of the hydrogen-cooled turbine generator 1, and hydrogen gas piping. Because there are other factors such as malfunctions, it is often not possible to make an immediate determination. Therefore, in order to detect this abnormality at an early stage during the microcracks, it is necessary to monitor the hydrogen gas that is separated and released in the space of the water storage tank 3. In addition, the above insulation tube 8.9
The insulation tubes 8 and 9 are made of materials that are permeable to hydrogen gas, such as polyfluoroethylene fiber tubes.
Even if the elements of the cooling water system including
Hydrogen gas as small as ay may enter the cooling water system.

On the other hand, the hydrogen gas carried to the water storage tank 3 is difficult to be sufficiently released into the atmosphere only by the respiration effect due to fluctuations in the water level of the water storage tank 3, the hydrogen gas passing through the atmospheric release pipe 12, and the diffusion phenomenon.

Therefore, hydrogen gas may accumulate in the space inside the water storage tank 3 and in the middle of the atmosphere discharge pipe 12, and the hydrogen gas concentration may reach the lower explosive limit concentration (4%) of hydrogen gas in the atmosphere. It is necessary to detect early signs of serious abnormalities such as the occurrence of cracks in the water system, and to take safe release measures against them.

The present invention provides highly reliable turbine generator cooling that can detect signs of serious abnormalities such as cracks in the in-flight cooling water system at an early stage and reliably, and can completely release hydrogen gas to the atmosphere. The purpose is to provide equipment.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention stores a fixed winding in which cooling water can flow inside a machine filled with hydrogen gas. In a cooling device for a turbine generator, the winding has an atmospheric discharge path for circulating cooling water stored in a water tank and for releasing hydrogen gas present in the upper space of the water tank into the outdoor atmosphere. , a hydrogen gas concentration detection passage communicating between the atmospheric discharge passage and the upper part of the water storage tank, and a hydrogen gas concentration detection passage provided between the hydrogen concentration detection passage and the communication portion between the atmospheric discharge passage and the water tank. a switching valve for switching the passage; a hydrogen gas concentration detector provided in the hydrogen gas concentration detection passage for detecting the hydrogen gas concentration in the water storage tank; and a hydrogen gas concentration detector based on the signal detected by the hydrogen gas concentration detector. a hydrogen gas concentration monitoring device that calculates the amount of hydrogen gas leaking from inside the aircraft and gives a switching command to the switching valve to open the atmospheric release path side when the leakage amount exceeds a predetermined value; The apparatus includes a N2 gas supply device capable of supplying N2 gas to the upper part of the water storage tank when a switching command is issued from the monitoring device.

(Function) Since the present invention is configured as described above, the hydrogen gas in the water tank circulates through the water tank, the hydrogen gas concentration detection passage, the hydrogen gas concentration detector, and the switching valve. When the concentration of hydrogen in the water tank increases in this state, it is detected by the hydrogen gas concentration detector, and the hydrogen gas concentration monitoring device monitors the hydrogen gas concentration when the concentration of hydrogen gas reaches the desired set value. The hydrogen gas in the water tank is released to the atmosphere by opening the atmospheric release path of the switching valve and closing the water tank side circuit in response to a signal from the device. At the same time, N2 gas is supplied into the water tank from the N2 gas supply device, so that both hydrogen gas and N2 gas in the water tank are completely scavenged. By performing these series of operations, the hydrogen gas concentration is detected, and the hydrogen gas concentration becomes below a certain predetermined concentration. At this time, the operation of the switching valve is switched to the hydrogen gas concentration detection passage on the water tank side, and the N2 gas supply is stopped, so that the hydrogen gas is circulated again and the hydrogen gas concentration in the water tank increases. .

As long as there is no abnormality in the generator through the above operations, the amount of hydrogen gas leaking from the cooling water system will be constant. Therefore, the hydrogen gas in the water tank is scavenged at regular intervals and monitored to maintain a stable hydrogen gas concentration. Operation control is possible.

On the other hand, if an abnormality occurs in the cooling water system and the hydrogen gas concentration is detected earlier than the predetermined time, the hydrogen gas concentration monitoring device will generate an abnormality signal and take appropriate measures at an early stage. You can take it. Furthermore, when the hydrogen gas concentration reaches a set value, N2 gas is supplied into the water tank, and the hydrogen gas in the water tank is quickly released into the atmosphere.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the schematic system diagram shown in FIG. 1. Here, the same parts as those in FIG.

A hydrogen gas concentration detection pipe 17 is provided that communicates between two points in the upper part of the water storage tank 3 and between the two points and the atmosphere discharge pipe 12, respectively.
This pipe 17 includes a fan 15 for forcibly circulating hydrogen gas in the water storage tank 3 containing hydrogen gas separated from the cooling water, and a hydrogen gas concentration for measuring the leakage amount of hydrogen gas contained in the gas in the water storage tank 3. Detector 13 and hydrogen gas concentration monitoring device 14
This is provided. Further, the pipe 17 is provided with an automatic three-way switching valve 16, which is switched between the atmosphere discharge pipe 12 side and the water storage tank 3 side in response to an output signal from the hydrogen gas concentration monitoring device 14, which will be described later. In addition, the atmosphere communication pipe 1 is connected to the atmosphere discharge pipe 12.
8 are connected to each other.

The automatic three-way switching valve 16 is configured to automatically switch between circulation on the water tank side and scavenging air discharged to the atmosphere in response to an output signal from the hydrogen gas concentration monitoring device 14 based on the hydrogen gas concentration. On the other hand, when the hydrogen gas concentration in the water storage tank 3 reaches a predetermined value, the automatic three-way switching valve 16 is operated and the same signal is used to open and close the water storage tank, which is closed during circulation and opened when released into the atmosphere.
A gas supply valve 19 is connected to the water storage tank 3 via an N2 gas supply device 21 and a N2 gas supply pipe 20. The hydrogen gas in the water storage tank 3 is scavenged by supplying N2 gas by opening the N2 gas supply valve 19. In addition, when the hydrogen gas concentration becomes below an arbitrary value in the hydrogen gas concentration monitoring device 14 provided on the hydrogen gas concentration detection pipe 17 due to the scavenging, the automatic switching valve 16 and the N2 supply valve are activated. 1
9, the air discharge side is opened, and the water storage tank 3 side is opened, and the N2 supply valve 19 is closed.

Hereinafter, the operation of the cooling system for a turbine generator of the present invention configured as shown in FIG. 1 will be described.

In FIG. 1, during normal operation of the turbine generator 1, hydrogen gas separated in the water storage tank 3 is first transferred by the fan 15 to the water storage tank 3, the hydrogen gas concentration detection pipe 17, the hydrogen gas concentration detector 13, and the hydrogen gas concentration detector 13. It circulates through the automatic three-way switching valve 16. Cooling water for cooling the conductors of the stator winding 2 of the turbine generator 1 is supplied to the stator winding 2 via the inlet header 7 and the insulating pipe 8.9 in the turbine generator 1, but the insulated Since the pipes 8 and 9 are made of polyfluoroethylene fiber pipes that permeate hydrogen gas, the hydrogen gas that is separated and released in the space of the water storage tank 3 gradually accumulates and the hydrogen gas concentration increases. come. Therefore, the detection signal detected by the hydrogen gas concentration detector 13 by the gas circulation in the water storage tank 3 by the fan 15 is amplified by the hydrogen gas concentration monitoring device 14, and the hydrogen gas concentration is set to an arbitrary set value, for example, the lower explosive limit (4 %)
When the following values are reached, the output signal from the hydrogen gas concentration monitoring device 14 causes the automatic switching valve 16 to open the atmosphere discharge pipe 12 side circuit and close the water tank 3 side circuit. The gas is scavenged by the fan 15.

On the other hand, since the hydrogen gas in the water storage tank 3 cannot be completely exhausted by the scavenging operation using only the fan 15, N2 gas is supplied into the water storage tank 3. When the N2 gas supply valve 19, which is automatically operated in conjunction with the automatic three-way switching valve 16, is opened, the N2 gas is supplied into the water storage tank 3, and the hydrogen gas is supplied together with the N2 gas by the operation of the fan 15. Completely scavenged.

As a result, the hydrogen gas concentration in the water storage tank 3 decreases, and if the hydrogen gas concentration detected by the hydrogen gas concentration detector 13 becomes below a certain predetermined concentration, for example (0.5%), the hydrogen gas concentration is monitored. The automatic three-way switching valve 16 is switched to the circulation circuit on the water tank 3 side by the output signal from the device 14, and the N2 gas supply valve 19 is closed, so that the hydrogen gas in the water tank 3 is circulated again in the same manner as described above. As a result, hydrogen gas permeates from the insulating pipes 8 and 9 in the generator 1 to the cooling water system, and the hydrogen gas concentration in the water tank 3 gradually increases. Therefore, if there is no abnormality in the generator 1, the insulation tube 8
．． Since the amount of hydrogen gas leaking from the tank 9 to the cooling water system is constant, the hydrogen gas in the water tank 3 is scavenged at regular intervals, and the hydrogen gas concentration is monitored and the operation is controlled to maintain a stable hydrogen gas concentration.

On the other hand, if an abnormality occurs in the cooling water system of the turbine generator 1 as described above and hydrogen gas abnormally leaks into the cooling water system, the hydrogen gas concentration in the water storage tank 3 will reach the lower explosive limit (4%).
If the time at which the hydrogen gas concentration is reached is detected abnormally earlier than the predetermined time, the hydrogen gas concentration monitoring device 14 generates an abnormality signal, so that appropriate measures can be taken at an early stage.

Next, the operation of this embodiment will be explained with reference to FIG.

In Figure 2, the solid line indicates normal operation with no abnormality in the turbine generator 1, and the dotted line indicates that an abnormality has occurred in the cooling water system of the turbine generator 1 and the amount of hydrogen gas leaked has increased. It shows the case.

As mentioned above, when the hydrogen gas concentration in the water storage tank 3 reaches L2, the automatic three-way switching valve 16 is switched to the atmosphere communication pipe 18 side, and the N2 gas supply valve 19 is opened to supply N2 gas into the water storage tank 3. Since the inside of the water storage tank 3 is scavenged, the hydrogen gas concentration detected by the hydrogen gas concentration detector 13 becomes L + again.
, decreases in the direction.

Then, the automatic three-way switching valve 16 is switched again to the water tank 3 side circulation circuit, and the N2 gas supply valve 19 is closed, so that the hydrogen gas concentration in the water tank 3 increases again. Therefore, by measuring the increase time T of hydrogen gas concentration -L2 and knowing the rate of increase in hydrogen gas concentration, it is possible to determine the amount of hydrogen gas that can be mixed into the cooling water system of the turbine generator 1 and the cooling water system during normal operation. It is possible to understand the degree of abnormality and easily compare it with abnormal conditions. Furthermore, as mentioned above, the hydrogen gas concentration in the water storage tank 3 was detected to be below the lower explosive limit (4%) and the N
2 gases are supplied and hydrogen gas is completely released into the atmosphere at an early stage.

[Effects of the Invention] As explained above, according to the present invention, signs of serious abnormalities such as cracks in the cooling water system in a hydrogen-cooled turbine generator can be detected early and reliably, and hydrogen gas release can be completely prevented. Accordingly, it is possible to provide a highly reliable cooling system for a turbine generator.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic system diagram showing an embodiment of the cooling system for a turbine generator of the present invention, FIG. 2 is a diagram for explaining the operation of the embodiment of FIG. 1, and FIG. FIG. 3 is a schematic system diagram showing an example of a stator winding cooling device for a conventional hydrogen-cooled turbine generator. 1... Turbine generator, 2... Stator winding, 3...
・Water tank, 4...pump, 5...cooler, 6...
Water supply pipe, 7...Population header-8...Insulation pipe, 9...
・Insulation pipe, 10... Outlet header - 11... Return pipe,
12... Atmospheric discharge pipe, 13... Hydrogen gas concentration detector, 14... Hydrogen gas concentration monitoring device, 15... Fan, 16... Automatic switching valve, 17... Hydrogen gas concentration detection Service pipe, 18... Atmospheric communication pipe, 19... N2 gas supply valve, 20... N2 gas supply pipe, 21... N2 gas supply device. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Scope of Claims] A fixed winding through which cooling water can flow is housed in a machine filled with hydrogen gas, and cooling water stored in a water tank is circulated through the stator winding, and the above-mentioned In a cooling device for a turbine generator having an atmospheric release path for releasing hydrogen gas present in an upper space in a water storage tank into the outdoor atmosphere, the hydrogen gas that communicates between the atmospheric release path and the upper part of the water storage tank is provided. a gas concentration detection passage; a switching valve provided between a communication portion between the hydrogen concentration detection passage and the atmosphere discharge passage and the water storage tank to switch the hydrogen gas passage; and a switching valve provided in the hydrogen gas concentration detection passage. , a hydrogen gas concentration detector that detects the hydrogen gas concentration in the water storage tank, and a hydrogen gas leakage amount from the inside of the machine based on the signal detected by the hydrogen gas concentration detector, and this leakage amount is a predetermined value. a hydrogen gas concentration monitoring device that issues a switching command to the switching valve to open the atmospheric release path side when the hydrogen gas concentration exceeds 100%; and when a switching command is issued from the hydrogen gas concentration monitoring device, N_2 gas is A cooling device for a turbine generator, which is equipped with an N_2 gas supply device capable of supplying N_2 gas.