JPS6188739A - Monitoring system of cooling medium temperature for rotary electric machine - Google Patents

Abstract

PURPOSE:To alarm the abnormal condition of stator coils, by metering the cooling medium temperatures of every outlet of cooling medium passages in a plurality of stator coils, and by finding the respective temperature differences. CONSTITUTION:Cooling medium temperatures T1-Tn at the outlets of each cooling medium passage are detected by thermometric elements 21 provided every stator coils 3, and armature current Iph is detected by a current transformer 27, and the respective detection signals are read into the RAM for a micro-computer 29 through conversion elements 25 and a converter 28, and P.U.-converted current values I are computed by operation. Then, temperature differences are found by two or more thermometric elements 21, and it is detected whether or not any of the signals of the temperature differences found in this manner comes to the range of set temperatures based on generator output namely armature current, and in case that the signal comes to the set temperature range, an alarm is worked according to the detection output.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooling medium temperature monitoring system for a rotating electrical machine that monitors the cooling medium temperature at the outlet of a cooling medium passage provided inside a stator coil.

[Conventional technology]

Conventionally, as this type of device, there have been cooling medium temperature monitoring devices for turbine generators as shown in FIGS. 5, 6, and 7. Figure 5 is a diagram showing the ventilation inside the turbine generator, Figure 6 is a sectional view of the stator coil, and Figure 7 is a circuit diagram for monitoring the coolant temperature at the outlet of the coolant passage of the stator coil. FIG.

In FIG. 5, reference numeral 1 denotes a generator frame, which has an airtight structure in order to seal hydrogen gas inside the generator. 2 is a stator core, 3 is a stator coil, 4 is a rotor, 5 is a bearing that supports both ends of the rotating shaft 48 of the rotor 4, 6 is a blower protruding from the outer periphery of one end of the rotor 4, and 8 is a hydrogen gas cooler. It is 2. 't fC, Gl is an arrow indicating the direction of flow of low-temperature hydrogen gas, G! is an arrow indicating the direction of the flow of hydrogen gas inside the stator coil 3, Gs is an arrow indicating the direction of the flow of hydrogen gas at the outlet of the cooling medium passage provided inside the stator coil 3, and G4 is an arrow indicating the direction of the flow of hydrogen gas inside the rotor coil. 2 is an arrow indicating the direction of flow of hydrogen gas in FIG.

Next, let's talk about the cooling effect of hydrogen gas.
Hydrogen gas is sealed within the frame 1, and is sent to the gas cooler 7 by the blower 6 and cooled by the rotation of the rotor 4. The cooled low-temperature hydrogen gas 8 flows in the direction of the arrow G, passes from the gas inlet of the stator coil 3 through the interior of the stator coil 3 in the axial direction (direction of the arrow Gx), and enters the stator coil 3. The heat generated due to resistance loss is removed, and it becomes high temperature hydrogen gas, which flows from the exit of the cooling medium passage of the stator coil 3 in the direction of arrow G! ejected in the direction.

On the other hand, the low-temperature hydrogen gas that has entered the rotor coil of rotor 4 moves in the axial direction (
It flows in the direction of arrow G4), absorbs the heat generated in the rotor coil, becomes high temperature hydrogen gas, and is discharged from the center of the rotor coil.

These high-temperature hydrogen gases are sent to the gas cooler 7 by the blower 6, where they exchange heat with cooling water and become low-temperature gas.
Again, each of the above arrows Gt, G2. Ga circulates in the direction of G4.

In addition, the structure near the stator coil 3 is K as shown in Fig. 6.
It has become. In the same figure, a 12fiH stator core, a 13fiH stator core,
is a stator slot 13, and the stator coil 3 is inserted into this slot 13. 14 is a stator coil 30 ground insulating member, 15 is a stator coil conductor, and 16 is this conductor 1.
This is a ventilation pipe buried inside 5. The ventilation pipe 16 is provided over the entire length of the stator coil, and hydrogen gas passes through the ventilation pipe 16 to cool the stator coil 3. The stator coil 3 is connected to the stator slot 13 from the slot wedge 20fC with spacers 18 and 19 interposed therebetween.
It is held inside to prevent it from escaping.

Further, a cooling medium temperature monitoring circuit is shown in FIG. The hydrogen gas absorbs the heat of the stator coil 3 as it passes through the stator coil 3, and the hydrogen gas absorbs the heat of the stator coil 3, and the hydrogen gas absorbs the heat of the stator coil 3 and passes through the cooling medium passage outlet stub ventilation pipe 16.
is discharged from the outlet. Reference numeral 21 denotes a temperature measuring element provided at the outlet of the cooling medium passages of the plurality of stator coils 3, and measures the temperature of the hydrogen gas discharged from the outlet. Temperature measuring element 2
The temperature signal from 1 is input to a recorder 22 and a notification device 23.

The alarm device 23 always collectively monitors the temperature signals from all the temperature measuring elements 21, and issues an alarm when the temperature detected by any of the temperature measuring elements exceeds a preset alarm value. This value is determined to be a constant value depending only on the temperature measurement data, regardless of the magnitude of the load on the generator, that is, the magnitude of the armature current. FIG. 8 is a graph showing the relationship between the armature current, the coolant temperature at the outlet of the coolant passage, and the alarm value. Note that here, the increase in the coolant temperature at the rated armature current is expressed as 1 (p, u,)
It is expressed as .

[Problem that the invention seeks to solve]

Since conventional cooling medium temperature monitoring is configured as described above, an alarm is generated when any one of the temperature signals detected by each temperature measuring element of the plurality of stator coils 3 exceeds the above information value. There have been problems in that it is difficult to discover abnormalities in the stator coil until the abnormality occurs, and prompt treatment cannot be taken after the abnormality occurs.

In addition, the coolant temperature at the outlet of the coolant passage of the stator coil changes depending on the magnitude of the armature current, but it is constant regardless of the above alarm value or the armature current, so in the area where the armature current is small, In areas where there is a large difference between the 7f alarm value and the temperature of the armature, it is not possible to correctly determine whether there is an abnormality in the stator coil unless the temperature of the armature rises above a considerable level. However, there was a problem in that it was easy to issue the alarm by mistake.

Furthermore, in order to detect an abnormality in the stator coil 3 before an E alarm occurs, conventionally the operator has to compare changes in the armature current with time changes in all the temperature values displayed on the temperature recorder. Therefore, the operator's fatigue due to constant monitoring is significant, and the determination of whether or not the stator coil 3 is abnormal has largely relied on experience, resulting in erroneous judgments.

The present invention was made in order to eliminate the problems of the conventional ones as described above, and it automatically compares the temperature signals obtained by the temperature measuring elements at the exits of the cooling medium passages provided inside all stator coils. The object of the present invention is to provide a cooling medium temperature monitoring device for a rotating electrical machine that can issue an alarm when the automatically compared temperature difference reaches a value outside a preset alarm value range according to the generator output. It is. This makes it possible to detect abnormalities in the starting rFL aircraft early, prevent accidents, and reduce the burden on the operator.

[Means for solving problems]

The present invention measures the temperature at the outlet of the cooling medium passage in the stator coil for each of a plurality of stator coils, determines the temperature difference between the two or more measured temperatures, and determines whether any of the determined temperature differences will cause the generator to An alarm is issued when the output exceeds a preset alarm value.

[For production]

According to this invention, the temperature of the cooling medium is measured by the temperature measuring element at the outlet of each cooling medium passage of the stator coil, and the temperature measurement signal is inputted to the temperature difference monitoring circuit, and the temperature measurement signal is inputted to the temperature difference monitoring circuit. A temperature difference signal is obtained for the signal, and it is detected whether any of the temperature difference signals obtained in this way reaches a set temperature range as soon as the generator output, that is, the armature current, and whether or not the set temperature range is reached. In such a case, the obituary alarm device is activated based on the detection output to warn of an abnormality in the stator coil.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 21 is a temperature measuring element provided at the outlet of the cooling medium passage provided in each stator coil 3, 22 is a temperature measuring recorder connected to a large number of temperature measuring elements 21, and 23 is a temperature measuring element connected in the same way. Alarm elements that display sound or light are used. Further, a temperature difference monitoring circuit 24 is connected to the temperature measuring element 21 to process and calculate the difference between the two temperatures to be measured, and the operation of the alarm device is controlled based on the output of this temperature difference monitoring circuit 24. FIG. 2 specifically shows such a temperature difference monitoring circuit 24. In this circuit, the temperature measurement signal of the temperature measurement element 21 is inputted to each conversion element 25 provided for each fixed coil 3 via a cable as a change in the resistance value of the temperature measurement resistor or a change in the voltage generated by the thermocouple. Ru. Each conversion element 2
In step 5, for example, this input signal is integrated over time and output as a stable analog signal, which is then input to the microcomputer 29. On the other hand, the armature current of the generator is detected by a current transformer 27 installed in a bus that leads the generated power to a main transformer (not shown), and this detected current is input to a converter 28. This is input to the microcomputer 29 as a signal corresponding to the magnitude of the armature current. 30 is an indicator, and microcomputer 2
The above-mentioned temperature difference and the magnitude of the armature current as outputs of 9 are constantly displayed to the operator, and when the temperature difference exceeds the above-mentioned alarm value, the death alarm device 23 is activated. ing.

Next, the operation of the cooling medium temperature monitoring device having the above configuration is as follows.
A detailed explanation will be given focusing on the flowchart shown in FIG.

(a) First, the temperature measuring element 21 provided for each of the plurality of stator coils 3 detects the coolant temperature Tl-Tn at the outlet of each coolant passage, and the current transformer 27
The armature current Iph is detected from , and each of these detection signals is read into the base M of the microcomputer 29 through the conversion cable 25 and the converter 28 .

(b) The processor calculates p, u, and the converted current value from the armature current read into the RAM and the rated armature current previously stored in the ROM.

(C) Next, the processor determines whether this current value is larger or smaller than, for example, 0.7, which is a value that greatly affects the temperature measuring element 21.

(d) If the result of this judgment is I) 0.7, the temperature ΔT ANN as the preliminary alarm value is set as Δ'rHX I"
and set.

(e) In addition, when the temperature is 0.7, the temperature ΔTANN as an alarm is set to ΔTL.

(f) Next, the temperature difference ΔT between two or more temperature measuring elements
Find i. This temperature difference ΔTi is used to determine the temperature difference between, for example, two temperature measuring elements 21 provided in all the stator coils 3.

(g) It is determined whether the plurality of temperature differences ΔTi thus obtained are larger than the alarm value ΔTANN. In other words, ΔTi
(h) If ΔTi≧ΔTANN as a result of this determination, the microcomputer 29
3 to notify the driver that the stator coil is abnormal.

By the way, in the temperature difference monitoring operation described above, even when each stator coil 3 is normal, the coolant temperature at the outlet of each coolant passage varies by about 4 to 5 degrees Celsius at the generator rated current. Therefore, in order to reduce the influence of such variations and improve monitoring accuracy, it is necessary to set two temperature-measuring elements for each temperature-measuring element located at a location where there is a small difference in coolant temperature based on the test run results of the generator. It is desirable to monitor the temperature difference between the two temperature measuring elements of each set, and to issue an alarm when this temperature difference exceeds a set alarm value.

In this way, if an abnormality occurs in any of the stator coils 3, one of the normal temperature measuring elements 21 will be used as a reference.
It becomes easier to detect the tendency and magnitude of the temperature difference between the output of the temperature measuring element 21 and the output of the other temperature measuring element 21. Finally, if the tendency of the temperature difference is monitored by the indicator 30, an abnormality can be detected in relation to the armature current before an alarm is issued.

In addition, as mentioned above, the refrigerant temperature for each stator coil 3 changes depending on the generator output, that is, the armature current, and
The temperature difference between the two thermometers increases as the armature current increases. Therefore, the alarm value is set as shown in FIG. 4 according to the armature current. Note that the alarm value corresponding to the armature current is stored in the ROM of the microcomputer 29.
It is stored in. Here, the allowable value of the temperature difference between the two temperature measuring elements 21 is set as i (p, u-), and this value can be adjusted in each generator. Furthermore, when the generator is under low load, the temperature difference in the visual report area becomes small, so there is a risk that false awning reports will occur. Therefore, the minimum value of the temperature difference between the two temperature measuring elements 21 is limited in advance.

In the above embodiment, a turbine generator in which the stator coil 3 is cooled with hydrogen gas has been described, but the present invention can also be applied to a turbine generator in which the stator coil 3 is cooled with water or oil.

In addition to directly measuring the temperature of the cooling medium, the temperature of each stator coil may be measured using a temperature measuring cord embedded between each stator coil.

〔Effect of the invention〕

As described above, according to the present invention, the coolant temperature at each outlet of the coolant passage in a plurality of stator coils is measured using a unique temperature measuring element, and the temperature difference between the two or more measured temperatures is calculated. If either of these temperature differences exceeds a preset alarm value depending on the magnitude of the armature current, it is determined that there is an abnormality in the stator coil and an alarm is issued. In particular, it is possible to prevent thermal or insulation failures due to insufficient cooling of the stator coil, and to improve the reliability of the generator.

Moreover, the automatic monitoring using the above-mentioned warning can provide effects such as reducing the labor burden on the operator.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a cooling medium temperature monitoring device for a rotating electric machine used to implement the method of the present invention, Fig. 2 is a circuit diagram for monitoring a temperature difference in the cooling medium, and Fig. 3 shows the flow of the circuit operation in Fig. 2. The flowchart shown in Figure 4 shows the setting alarm for armature current (
5 is an explanatory diagram showing the structure and cooling gas flow system of a conventional turbine generator, which is the basis of the present invention, and FIG. 6 is a sectional view of the vicinity of the stator coil.
FIG. 7 is an explanatory diagram of a conventional coolant temperature monitoring circuit, and FIG. 8 is a graph showing the relationship between the set alarm value and the armature current in the same conventional case. In the figure, 3 is a stator coil, 4 is a rotor, 7 is a gas cooler, 12 is a stator core, 16 is a ventilation pipe, 21 is a temperature measuring element, 23 is a fraud device, 24 is a temperature difference monitoring circuit, and 27 is a Current transformer, 30 is an indicator. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (3)

[Claims] (1) In a rotating electric machine in which the stator coil is cooled by flowing a cooling medium through a cooling medium passage provided inside the stator coil, the temperature of the cooling medium at the outlet of the cooling medium passage is determined by the stator coil. The temperature difference between the two or more measured temperatures is determined, and an alarm is issued when any of the determined temperature differences exceeds a preset alarm value depending on the generator output. A cooling medium temperature monitoring method for rotating electric machines characterized by: (2) For the temperature measuring elements that measure the coolant temperature at the outlet of the coolant passage, select two temperature measuring elements each in areas where there is a small temperature difference in the coolant, and alarm the measured temperature difference between these temperature measuring elements. 2. A cooling medium temperature monitoring method for a rotating electric machine according to claim 1, wherein the cooling medium temperature of a rotating electric machine is compared with a value. (3) Cooling of the rotating electric machine according to claim 1, characterized in that the generator output is obtained from a current transformer installed in a bus bar connected to the main transformer that receives this output. Medium temperature monitoring method.