JPS6327651B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A closed electric machine, in which leakage of cooling water in the water-cooled coils of a stator of the electric machine is additionally circulated through which a flow of hydrogen gas cooled by a heat exchanger In order to detect by measuring the humidity inside the casing and to establish and maintain a constant humidity state of the gas flow inside the electromechanical casing,
Humidity measurement methods have already been proposed in which the dew point is determined in the region of the cooling gas stream by means of a separately provided temperature drop and the humidity change, which deviates from a steady state, is subsequently measured. The present invention relates to a method for detecting a leak of cooling water according to this method, and an apparatus for implementing the method.

In the previously proposed humidity measuring method, first a steady humidity state is established for the cooling gas flow,
As a result, any subsequent changes in humidity give a clear inference to cooling water leaks. When using this method, leaks of cooling water are detected and also condensation of moisture on hazardous electrical machine parts is largely avoided. Water leaks, which can be detected via changes in humidity, occur in the water-cooled coils of the electrical machine, ie the water-cooled stator coils or, as the case may be, the water-cooled rotor coils. However, in addition, water leaks in the cooling pipes of the heat exchanger for the cooling gas are also detected. Therefore, it is impossible at this time to state whether the detected water leakage is due to a leakage point in the coil or in the heat exchanger.

Therefore, this invention improves the previously proposed humidity measurement method by
The purpose of this invention is to improve the ability to separate and detect water leaks that occur in water cooling coils in some cases from other water leaks.

Such purpose is achieved according to the invention by adding an easily detectable indicator to the cooling water of the coils and monitoring the presence of this indicator in the condensed water formed in the temperature drop section. This is achieved by In the unlikely event that a leak occurs in the water-cooled coil, the detected leak may be due to other causes, especially a heat exchanger leak. It is based on location. The method according to the invention therefore makes it possible to unambiguously state whether a water leak exists in the water-cooled coil of an electrical machine. Such a statement regarding the source of the leak is extremely important, since it is necessary to know the cause of the incident in order to overcome the obstacle, limit the damage or eliminate the damage in a timely manner.

Indeed, a device for detecting water leakage points in the cooling water circuit of an electrical machine is already known from German Patent Publication No. 21 54 979. In this invention, a tritium radioactive isotope supply device is connected to the cooling water supply pipe as an indicator. Furthermore, an isotope counter is additionally connected to the exhaust pipe for a partial flow of the cooling gas stream in the housing of the electrical machine. As a result, in the event of a water leak, tritium appearing in the cooling gas can be detected using an isotope counter. However, this known device is not suitable for separately detecting leak points in various cooling water circuits. Furthermore, markings added to the cooling water circuit are inherently easier to detect in condensed water than in cooling gas, in the event of a leak of relatively small proportions. Can be detected.

In the method of this invention, a substance that can be easily detected chemically or physically can be used as a marker. It is therefore possible, for example, to use luminescent dyes as indicators, but in particular radioisotopes are used. In this case, the radioactive isotope in the form of tritium is such that the special effects that occur upon its use are physiologically harmless;
Moreover, it can be easily detected in a small amount, making it particularly suitable as a sign.

The invention furthermore provides a device for carrying out the method of the invention, which has an external gas dryer and a humidity measuring device arranged in parallel to the cooling gas stream as a temperature reduction section. The device also includes a marking supply device connected to the cooling water circuit of the train, a condensed water storage tank connected to the gas dryer, and a detector located in the condensed water storage tank and capable of responding to the markings. . In this case, the indicator supply device and the detector make it possible to isolate and detect water leaks occurring in the water-cooled coils with only a small investment in equipment.
It is particularly advantageous to use a transmitter as a detector. If radioactive material is used as the indicator, the transmitter can make quantitative statements regarding the amount of indicator contained in the condensed water. With this quantitative statement, in addition to the water leakage detected in the coil,
At the same time, it is also possible to detect whether other leaks exist elsewhere, for example in the heat exchanger.

Next, embodiments will be described in detail based on the drawings.
In this case, the drawing shows, in a highly simplified schematic representation, a longitudinal section through a generator with a cooling device installed in principle. As is clear from the drawings, a stator laminated core 2 having a water-cooled wire ring 3 and a rotor 4 are provided in a pressure-resistant and airtight generator casing 1. The rotor 4, which is driven by a turbine not shown in detail via the shaft 5, can likewise be water-cooled, as will be introduced in more detail later. In order to additionally cool the stator laminated core 2 and other parts of the generator, the casing 1 is filled with hydrogen gas as cooling gas. This cooling gas is circulated by fans 6 and 7 arranged on the shaft 5 and is recooled by a cooler 8 provided in part of the casing 1 at the end of the generator. In this case, the cooling gas flow is indicated by solid arrows 9 for recooled gas and dotted arrows 10 for heated gas.

Two separate cooling water circuits are provided to eliminate heat loss. In the first cooling water circulation path, so-called primary cooling water is supplied from the cooling water purification equipment 11 via the water supply pipe 12 to the annular pipe 13, and from there the water is further supplied to the individual hollow conductors of the stator coil 3. be done. The primary cooling water discharged from the stator coil 3 on the other side of the stator laminated core 2 is passed through another annular pipe 14 and a drain pipe 15 to a cooling water expansion tank 16 disposed in the upper part of the casing 1. be guided.
Furthermore, the primary cooling water is circulated from the cooling water expansion tank 16 via the piping 17 to the cooling water purification equipment 11 including a cooler and a pump (not shown in detail), and from there it is circulated through the stator coil 3 again. guided by the path. Next, in the second cooling water circuit, the so-called secondary cooling water flows through the individual cooling coils 18 of the cooler 8.
guided by. As is clear in the drawing,
The second cooling water circuit is also distributed into a number of partial circuits. In this case, cooling and purification of the secondary cooling water are not shown in detail.

In order to quickly detect water leakage that should occur inside the casing 1 in one of the two cooling water circulation paths described above, a constant humidity state of the cooling gas is created inside the casing 1. As a result, a unique result can be obtained by measuring humidity to detect cooling water leaks. For this purpose, a certain dew point must be created inside the cooling gas circuit, which represents the lowest point of system temperature and which therefore cannot be lowered under any operating conditions nor by other parts of the electrical machine. A temperature drop area must be created where the temperature is determined. For this purpose, a bypass pipe 19 for the cooling gas circuit is provided.
A gas dryer 20 is provided with a cooler 21 of conventional configuration therein, the moisture condensing in the cooler,
The condensed water 22 is led to a condensed water storage tank 24 via a pipe 23. This condensed water storage tank 24
is sometimes drained via a drain valve 25, but this draining can also be carried out automatically by means of a water level gauge. A humidity measuring device 27 is also provided in another bypass pipe 26 of the cooling gas circulation path, with which it is possible to detect changes in humidity as well as its absolute value. Humidity measuring device 2
7 can be used to measure the humidity fluctuations that deviate from a steady humidity state, it is possible to estimate a leak in either of the two cooling water circuits.

In this way, the presence or absence of a water leak can be detected by measuring the humidity, but it is still not possible in this case to make a statement as to which of the cooling water circuits the detected water leak is present. However, such a statement is important because water leakage in the coils should be taken seriously and can result in serious damage.

In order to distinguish water leakage that appears in the first cooling water circulation path of the train from water leakage that appears elsewhere, an indicator is mixed into the primary cooling water of the first cooling water circulation path, and an indicator is mixed into the primary cooling water of the first cooling water circulation path, The presence of this indicator is monitored by the condensed water that forms. For this purpose, a supply device 28 is connected to the line 17 via which radioactive tritium as a marker is added to the primary cooling water. However, the supply of tritium is then possible at any other location in the first cooling water circuit. If water leaks in the stator coil 3, the tritium will drain the condensed water 22 through the cooling gas.
It reaches inside and is detected there. For the purpose of detecting tritium, a transmitter 29 is provided as a detector in the condensate tank 24, which generates a signal indicated by arrow 30. Therefore, if there is a water leak detected by the humidity measuring device 27, this signal 30 determines whether tritium is present in the condensed water 22, i.e. whether the detected water leak is in the first cooling water circulation. It is possible to inductively infer whether something is on the road or not.

As already mentioned above, the rotor of the generator can also be equipped with water-cooled coils. Therefore, in this case, the branch pipe 31 and the cooling water connection joint 3 are additionally connected to the primary cooling water supply pipe 12.
2, a part of the primary cooling water is led to the shaft 5,
After flowing through the rotor coil, the water is drained from the rotor again via the cooling water connection joint 32. Then, through another pipe 33, the stator cooling water is led to the cooling water expansion tank 16 by the drain pipe 15.
will be guided to. In this case too, a leak in the rotor coil 4 or, as already mentioned, in the stator coil 3 is indicated by a corresponding signal 30 of the transmitter 29.

By means of the invention, any leakage in the housing of an electrical machine is therefore detected, and leaks in the stator or rotor wheels, which should be taken into particular consideration, are therefore indicated. Early recognition of water leaks of this type makes it possible to reliably prevent further damage to the electrical machine.

As explained above, the present invention solves the leakage of cooling water in at least the water-cooled coils of the stator of an electric machine by shutting it down through which a flow of hydrogen gas cooled by a heat exchanger additionally circulates. The humidity inside the housing of the electromechanical machine is detected by measuring the humidity, with a separate temperature reduction part provided in order to create and maintain a constant humidity state of the gas flow inside the electromechanical housing. A method for detecting a cooling water leak, which is carried out according to already proposed humidity measurement methods, in which the dew point is determined in the region of the cooling gas flow and subsequently the change in humidity displaced from a steady state is measured.
By adding an easily detectable indicator to the coil cooling water and monitoring the presence of this indicator by condensation forming in the temperature drop zone, the It is possible to easily and clearly distinguish between water leakage and water leakage in other parts of the electric machine and to detect it, and therefore, it is possible to prevent unexpected accidents in the electric machine due to water leakage in the wire wheels.

[Brief explanation of the drawing]

The drawing represents, in a highly simplified schematic representation, a longitudinal section of the generator with the basic piping of the cooling device. 1: Generator casing, 3: Stator coil, 4:
Rotor, 20: Gas dryer, 22: Condensed water, 2
4: Condensed water storage tank, 27: Humidity measuring device, 2
8: Sign supply device, 29: Transmitter.

Claims (1)

[Scope of Claims] 1 Cooling water in the water-cooled coil of the stator of a closed electric machine in which the stator coil is water-cooled and a hydrogen gas flow cooled by a heat exchanger circulates in the casing. In order to detect water leakage, measuring and detecting humidity inside the casing;
In order to establish and maintain a constant humidity state of the gas flow inside the electromechanical housing, the dew point is established by means of a separate temperature drop in the area of the cooling gas flow, and then a constant In a cooling water leakage detection method carried out in accordance with a humidity measurement method that measures changes in humidity from a normal state, an easily detectable indicator is added to the cooling water of a coil, and a marking is formed at a temperature drop part. A method for detecting a leak of cooling water, the method comprising: monitoring whether this indicator is present in condensed water. 2. In the method described in claim 1,
A method for detecting cooling water leakage, characterized in that a radioactive substance is used as an indicator. 3. In the method described in claim 2,
A method for detecting a leak of cooling water, characterized in that a radioactive lysotope similar to tritium is used as an indicator. 4. To detect leakage of cooling water in the water-cooled coil of the stator of a closed electric machine in which the stator coil is water-cooled and a hydrogen gas flow cooled by a heat exchanger circulates in the casing. , measuring and detecting humidity inside the casing;
In order to create and maintain a constant humidity state of the gas flow inside the electromechanical housing, a temperature reduction section consisting of an external gas dryer and a humidity measuring device arranged in parallel to the cooling gas flow is used. The dew point is then determined by adding an easily detectable indicator to the coil cooling water and monitoring the presence of this indicator in the condensed water formed in the temperature drop section. A device for detecting leakage of cooling water is a device for supplying signs connected to the cooling water circulation path of the train, a condensed water storage tank supplied to the gas dryer, and a sign provided in the condensed water storage tank. A device for detecting a leak of cooling water, comprising a detector that responds to an object. 5. In the device according to claim 4,
A device for detecting cooling water leakage, characterized in that the detector is a transmitter.