JPH0339256B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a vibration monitoring device for a rotating machine that monitors vibrations in a generator or other rotating machine and issues a trip command when abnormal vibration occurs.

[Technical background of the invention]

Turbines in thermal power plants and nuclear power plants
In large rotating machines such as generators, when an abnormality occurs in the rotating system, it is necessary to stop the rotating machine immediately to prevent the problem from spreading and secondary disasters to occur.

Since mechanical abnormalities in rotating machines often manifest themselves as increased vibrations, large-sized rotating machines have traditionally been equipped with vibration monitoring devices.

Figure 1 shows three steam turbines 1a, 1b, 1
This example shows a turbine/generator connected in series to the generator 2 and a vibration monitoring device installed therein.
Vibration detectors 3a, 3b, 3 attached to the bearings of
The vibration signals from c, . . . , 3h are converted into electrical signals by signal converters 4a, 4b, 4c, .

The electronic computer 5 calculates the electrical signals from each signal converter 4a to 4h and determines whether the vibration of the rotating system is within a normal range (safety range), within a range that requires attention (caution range), or It is determined whether the system is in an abnormal range (stop area), and if it is in the caution area, it outputs a caution signal, and if it is in the stop area, it outputs a trip signal to stop the rotation system.

In addition, in the vibration monitoring device shown in Fig. 1, the signal converter 4
After converting the vibration signal into an electric signal by a to 4h, it is introduced into the electronic computer, but the use of the signal converters 4a to 4h is omitted and the output of the vibration detectors 3a to 3h is directly transmitted. In some cases, the data may be input to the electronic computer 5.

By the way, it is extremely important to trip rotating machinery immediately in the event of an accident to ensure safety, but on the other hand, it is extremely important to trip rotating machinery immediately when an accident occurs.
In the case of important equipment such as a generator, a trip can have a major impact on the power system, so it is necessary to avoid unnecessary trips as much as possible.

Therefore, in the vibration monitoring device, a normal trip circuit with a two-loop configuration is provided in the electronic computer, and a backup trip circuit is also provided.
It is designed to prevent mistrips.

FIG. 2 shows a logic diagram of a trip circuit in a conventional vibration monitoring device. In the same figure, the normal trip circuit 6 is connected to the nth bearing (n is an integer of 1 or more).
The vibration at is greater than the first stage trip value (A),
The AND circuit 7 is configured to generate an output on the condition that the vibrations in the bearings other than the n-th bearing exceed the alarm value (B). Further, the backup trip circuit 8 generates an output on the condition that the vibration at the n-th bearing is equal to or higher than the second stage trip value (C). The outputs of these trip circuits 6 and 8 pass through an OR circuit 9 and are output as a trip command.
The relationship between the trip value and the alarm value described above is such that the second stage trip value>the first stage trip value>the alarm value.

Therefore, when the vibration at any two vibration detection points exceeds a specified value, the normal trip circuit 6 outputs a trip command through the OR circuit 9, and if for some reason the normal trip circuit 6 If it does not work, a trip command is output by a signal from the backup trip circuit 8.
In this case, since the trip circuit normally outputs a trip command when abnormal vibrations occur simultaneously in two bearings, a trip command will not be issued by mistake even if an abnormality occurs in one loop of the vibration measurement circuit.

[Problems with background technology]

However, the backup trip circuit is
If the vibration in any one bearing exceeds the limit value (second-stage trip value), a trip command is immediately sent, so if the measurement circuit malfunctions due to a failure of the vibration detector or alarm setting device, etc. There is an inconvenience that a mistrip command is output and the rotating machine is stopped even though it is not necessary.

[Purpose of the invention]

The present invention has been made to eliminate the above-mentioned disadvantages in the background art, and an object of the present invention is to provide a vibration monitoring device that prevents mistrips due to malfunction of the backup trip circuit.

[Summary of the invention]

In order to achieve the above object, the vibration monitoring device for a rotating machine of the present invention includes a backup trip circuit having a two-loop configuration in addition to the regular trip circuit configuration.
A trip command is output from the backup trip circuit on the condition that the vibration at the nth detection point is equal to or higher than the second stage trip value, and the vibration at any detection point other than the nth detection point is equal to or higher than the backup alarm value. The second stage trip value on the backup side is higher than the backup alarm value, and these are set at a higher level than the alarm value of the normal trip circuit.

[Embodiments of the invention]

Next, embodiments of the present invention will be described with reference to the drawings.

The basic configuration of the vibration monitoring device of the present invention is the same as that shown in FIG. That is, three turbines 1a~
When monitoring vibrations of a comb-shaped turbine/generator consisting of a generator 1c and a generator 2, the vibration detectors 3a to 3h detected by the vibration detectors 3a to 3h attached to the bearings of each rotating machine The vibration signals thus detected are input to the computer 5 directly or via signal converters 4a to 4h.

The vibration monitoring circuit set in the electronic computer 5 is
As shown in FIG. 3, it is comprised of a normal trip circuit 10, a backup trip circuit 11, and an OR circuit 12 that outputs a trip command in response to the output signals from these trip circuits.

Normally, the trip circuit 10 is as in the case of FIG.
The AND circuit 13 generates an output on the condition that the vibration at the n-th bearing is equal to or higher than the first stage trip value (A), and the vibration at the bearings other than the n-th bearing is equal to or higher than the alarm value (B). We are prepared. In addition, the backup trip circuit 11 is configured such that the vibration at the n-th bearing is
An AND circuit 14 is provided which generates an output on condition that the vibration is equal to or greater than the step trip value (C) and that vibrations in bearings other than the n-th bearing are equal to or greater than the backup alarm value (D).

Here, the relationship between each trip value and alarm value is 2nd stage trip value > 1st stage trip value ＞Backup alarm value ≧Alarm value It is said that

In a vibration monitoring device having such a configuration, if the detection signal from any one of the vibration detectors 3a to 3h exceeds an abnormal level, normally the trip circuit 10 and the backup trip circuit 11 will not produce an output. do not have.

On the other hand, any two vibration detectors 3a to 3
When the detection signal from h exceeds the alarm value, when one of them reaches the first stage trip value, the AND circuit 13 satisfies the output condition, so the output is normally sent from the trip circuit 10 to the OR circuit 12. An output signal is emitted toward the target, and a trip command is output.

In the above, if the trip circuit 10 normally does not operate due to an abnormality in the circuit components, the detection signals from any two vibration detectors 3a to 3h exceed the backup alarm value, and either one of the detection When the signal reaches the second stage trip value, an output signal is issued from the AND circuit 14 on the backup trip circuit 11 side to the OR circuit 12, and a trip command is output.

In this manner, in the vibration monitoring device for rotating machinery of the present invention, the normal trip circuit and the backup trip circuit each have a two-loop configuration, so that abnormal vibrations can be detected reliably. In other words, when an abnormality occurs in a rotating machine, it is extremely rare for abnormal vibration to occur in just one bearing, and in most cases, abnormal vibration also occurs in two or more bearings. By utilizing this phenomenon, the present invention can suppress the occurrence of mistrip commands due to abnormalities in circuit components, etc.

In the above explanation, the vibration detection point is set at the bearing, but the present invention is of course not limited to this, and the vibration detector may be set at an optimal position taking into consideration the properties of the rotating machine. can do.

〔Effect of the invention〕

As described above, in the vibration monitoring device for a rotating machine of the present invention, the normal trip circuit and the backup trip circuit each have a two-loop configuration, and the trip value and alarm value on the backup side are set at a higher level than on the normal trip circuit side. Therefore, if the trip circuit normally does not operate for some reason, a trip command can be issued by the output of the backup trip circuit, and an accident can be prevented by immediately stopping the rotating machine. It is possible to prevent the spread of damage and the occurrence of serious secondary disasters, and furthermore, it is possible to prevent mistrips caused by malfunctions of measurement circuits, etc.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an overview of a comb-shaped three-unit turbine/generator and a vibration detection device attached to it, Fig. 2 is a logic diagram of a conventional vibration detection device, and Fig. 3 is a vibration detection device of the present invention. FIG. 3 is a logic diagram in a detection circuit. 1a to 1c...turbine, 2...generator, 3a
~3h...Vibration detector, 4a~4h...Signal converter, 6,10...Normal trip circuit, 8,11...
...backup trip circuit.

Claims (1)

[Claims] 1. A vibration detector attached to multiple locations on a rotating machine;
In a vibration monitoring device for a rotating machine, which includes an electronic computer that processes signals from these vibration detectors and outputs a trip command in the event of an abnormality, the electronic computer has an n-th (n: an integer greater than or equal to 1) detection device. A normal trip circuit generates an output on the condition that the vibration at a point is equal to or higher than the first stage trip value and the vibration at a detection point other than the nth detection point is equal to or higher than the alarm value; and a backup trip circuit that generates an output on condition that the vibration is equal to or higher than the second stage trip value and the vibration at a detection point other than the nth detection point is equal to or higher than the backup alarm value, A vibration monitoring device for a rotating machine characterized in that the trip values and alarm values in the normal trip circuit and the backup trip circuit have the following relationship: 2nd stage trip value > 1st stage trip value > backup alarm value ≧ alarm value . 2. Claim 1, wherein the vibration detector is attached to each bearing of a rotating machine.
Vibration monitoring device for rotating machines as described in .