JPH0580160U - Failure monitoring device for generator stator - Google Patents

Abstract

(57) [Summary] [Objective] An object of the present invention is to provide a failure monitoring device of a generator stator capable of reliably detecting an internal failure of a generator stator coil having a plurality of gas cooling systems for each phase. And [Configuration] Circuit 3 for measuring the outlet temperature of the generator stator cooling gas for each phase cooling system with the temperature measuring element 1 and converting the measured value into a signal level, converting the generator output current detection value into a signal level Circuit 4, an arithmetic processing circuit 5 that takes in the outputs of both circuits, and an alarm device 6. The arithmetic processing circuit 5 calculates the difference between both temperature measurement values for each phase and also outputs an alarm threshold according to the generator output. A value is calculated, and when the calculated value exceeds the alarm threshold value, it is determined that the stator has an internal failure, and an alarm command is issued by the alarm device 6.
It is characterized by giving to.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a generator stator failure monitoring device.

[0002]

[Prior Art]

 FIG. 4 shows an example of a conventional generator stator failure monitoring method. With this method, when abnormalities such as wire breakage occur in the generator stator coil, the temperature of the hydrogen gas that cools the generator stator rises compared to during normal operation, and U, V, W The temperature of the generator stator gas for each phase is input to the recorder as an absolute temperature with a temperature measuring element, and the presence or absence of abnormality is detected by whether the temperature measured value exceeds the alarm value.

[0003]

[Problems to be solved by the device]

 FIG. 5 shows an example of the stator coil of the gas-cooled generator. The stator coil 10 of each phase U 1, V 2, W of the generator is divided into two coils 10A, 10B, and each coil 10A. 10B are cooled by separate cooling systems 11A and 11B as shown in FIG.

In such a generator stator coil, for example, even if a short circuit occurs in the coil 10A and the gas outlet temperature of the cooling system 11A rises, the gas outlet temperature of the cooling system 11B of the other coil 10B is increased. Since is a steady temperature, there was a problem that the conventional method of measuring at one point of each phase could not accurately detect the internal failure of the generator stator coil.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a failure monitoring device for a generator stator, which is more reliable than conventional ones.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention measures a gas outlet temperature of a generator stator cooling gas for each two cooling systems of each phase, a circuit for converting an output of a temperature measuring element into an electric signal, and a generator output current. It is equipped with a circuit that converts the detected value into a signal level and an arithmetic processing circuit that takes in the outputs of both circuits.The arithmetic processing circuit calculates the difference between both temperature measurement values for each phase and outputs the generator output. The alarm threshold value is calculated according to the above, and if the calculated value exceeds the above alarm threshold value, it is judged that the stator has an internal failure and an alarm signal is generated.

According to a second aspect of the present invention, each input value of the arithmetic processing circuit is averaged and an alarm signal is generated when the calculated value exceeds the temperature set value for a predetermined time.

[0008]

[Action]

 In the present invention, the outlet gas temperature is measured for each cooling system of each phase and the temperature difference is compared with the alarm threshold, so that even when one coil fails and the other coil is normal, the stator coil It is possible to reliably detect the internal failure of the.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a resistance temperature detector for measuring the temperature of the outlet gas of each of the cooling systems 11A and 11B of the generator stator. 2 is a current detector CT that detects the output current of the generator, 3 is a temperature / current converter, 4 is a current / current converter, 5 is a processing unit (CPU), 5AU and 5AW are temperature difference calculation units. 5B is a steady temperature difference calculation unit, an alarm value memory, 5C is a comparison unit, and 6 is an alarm device.

Next, the operation of this device will be described with reference to the logic chart shown in FIG. In this embodiment, the temperature measuring resistor 1 measures the gas outlet temperatures of the two cooling systems for each of the U, V, and W phases. The temperature measurement values at these two points are converted into a current signal of a signal level by the temperature / current converter 3 and taken into the CPU 5. When the current conversion values of the two temperature measurement values of the U phase are U ₁ and U ₂ , the temperature difference calculation unit 5U of the CPU 5 calculates the absolute value of the difference between the current conversion values U ₁ and U ₂ . Similarly, if the current conversion values of the two temperature measurement values of the W phase are W ₁ and W ₂ , the temperature difference calculation unit 5W of the CPU 5 calculates the absolute temperature difference value of the difference between the current conversion values W ₁ and W _2. Calculate The same applies to the V phase.

Based on the current value I output from the current / current converter 4, the steady temperature difference calculation unit 5B calculates the alarm threshold value (temperature difference of the outlet gas temperature at normal time) θ _ANN shown in FIG. Is calculated.

Θ _ANN = 4.0 × I ² (I> 0.7 pu) (1) θ _ANN = 2.0 (I < 0.7 pu) (2) where 1 pu is the generator rated output.

An area above the threshold of the curve shown by the solid line in FIG. 3 is the alarm area. The CPU 5 compares the temperature difference θ _ANN of the normal outlet gas temperature with the absolute value of the temperature difference. If the absolute value of the temperature difference is in the alarm range exceeding the alarm threshold value, the CPU 5 determines that the generator stator coil has an internal failure and sends an alarm command to the alarm device 6. The alarm device 6 gives an alarm.

By the way, the alarm threshold value in FIG. 3 is a theoretical value, and in actuality, the detected temperature and output current value have instantaneous variations that are singular points. This is done to prevent false alarms.

(1) In order to eliminate the singular point of the input value, each input value is averaged. (2) When an internal failure of the generator stator coil is detected, the alarm command is issued on the condition that this state has continued for a certain period of time. By storing the measured temperature, the detected current, the calculated absolute value of the temperature difference, and the like in the storage unit of the CPU 5, it is possible to confirm at which point the abnormality has occurred.

[0017]

As described above, the present invention measures the outlet gas temperature for each cooling system of each phase and compares the temperature difference with the alarm threshold, so that the internal failure of the generator stator coil is prevented. It can be surely detected, and the reliability can be improved as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a logic chart showing the operation of the above embodiment.

FIG. 3 is a diagram showing an alarm threshold value characteristic of the embodiment.

FIG. 4 is a flowchart illustrating a conventional method of monitoring a failure of a generator stator.

FIG. 5 is a diagram showing an example of a generator stator coil.

FIG. 6 is an enlarged view of a part of the generator stator coil.

[Explanation of symbols]

 1 Resistance Temperature Detector 2 Current Detector CT 3 Temperature / Current Converter 4 Current / Current Converter 5 CPU 5U, 5W Temperature Difference Calculator 5B Steady Temperature Difference Calculator 5C Comparison Unit 6 Alarm Device

Claims (2)

[Scope of utility model registration request] 1. A circuit for converting the output of a temperature measuring element, which measures the gas outlet temperature of the generator stator cooling gas for each two cooling systems of each phase, into an electric signal, and a detected output current value of the generator as a signal level. And a calculation processing circuit that captures the outputs of both circuits, and the calculation processing circuit calculates the difference between both temperature measurement values for each phase and also outputs an alarm threshold value according to the generator output. And an alarm signal is generated by determining that the internal value of the stator is in failure when the calculated value exceeds the alarm threshold value. 2. The input value of the arithmetic processing circuit is averaged, and an alarm signal is generated when the arithmetic value exceeds the temperature difference set value for a predetermined time.
Failure generator monitoring device for the generator.