JPS60132003A - Turbine protector - Google Patents

Abstract

PURPOSE:To prevent a manual, unnecessary turbine trip by displaying the shaft displacement and vibration based on shaft vibration signals obtained from turbine shaft vibration detectors via an earthquake filter when an earthquake occurs. CONSTITUTION:An earthquake filter 8b is provided between a turbine monitor panel 7 and an indicator 9c. Even if an earthquake of a specified value or less occurs, outputs of seismometers 20a-20z do not reach a preset value alpha, thereby a relay 22 is not operated and a contact 23 is opened, thus only a low-frequency cut filter 8a is connected to the output side of the turbine monitor panel 7. When the outputs of the seismometers exceed the preset value alpha, the relay 22 is operated and the contact 23 is closed, thus signals from shaft vibration detectors 5a-5n are fed to the displacement indicator 9c and a vibration recorder 9d with low-frequency components (25Hz or less) cut off by the earthquake filter 8b, and an operator can monitor by observing the displacement excluding the effect of the earthquake.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a turbine protection device for protecting a turbine constituting a power generation plant from abnormal conditions.

[Technical background of the invention]

Turbine protection systems in nuclear power plants, etc., issue an alarm or automatically stop the turbine depending on the degree of abnormality if the vibration of the turbine shaft exceeds normal values due to an earthquake, etc. It has the function of protecting the turbine by preventing (turbine trip).

A conventional turbine protection device is shown in FIGS. 1 to 1 of the accompanying drawings.
This will be explained with reference to the figures. In addition, in the following description of the drawings, the same elements are indicated by the same reference numerals. FIG. 1 is a front view of the vicinity of a turbine of a nuclear power plant. For example, a plurality of (for example, 4f) turbines 2@, 2b, .
...2m are installed in a line, and a generator 3 is installed at one end.

1-Via 2m to 2m, the generator 3 has a common turbine shaft≠ υ, and its bearing part has shaft vibration detectors (shaft displacement needles) ja, jb... ! n is provided. In addition, the turbine generator foundation / has a λ group! Seismometers 20 m = 20 d, 20w to 20z are arranged as shown.

FIG. 2 is a sectional view of the bearing portion of the shaft vibration detector ja of FIG. 1. The shaft vibration detector Za is fixed to the bearing 6 and detects the absolute displacement amount of the turbine shaft.

FIG. 3 is a configuration diagram of an example of a conventional device. The outputs (shaft vibration signals) of the shaft vibration detectors j and -tn are converted into signals by the turbine monitoring panel 7, and then passed through a low frequency cut filter ffs to the displacement display meter a1, which constitutes the display recording means, and the vibration recorder Pb. presented and recorded here. The shaft vibration signal is also given to the vibration relay board lno via the low frequency cut filter fa, and the magnitude of the displacement amount is determined here.

Then, it is determined whether the system is in an alarm state or the turbine trip is in a normal state, and the alarm device /:2 is activated and the turbine trip device /3 is activated via the timer 30m. Note that the timer 30m is used to control the turbine protection operation in a stable state rather than in a transient state.
The setting time is usually about 1 second.

The seismometers X)a-20d and KooW to KooZ detect earthquake-induced vibrations of the turbine generator foundation and apply them to the earthquake vibration relay board. Is the vibration of the seismic vibration relay board υ larger than the set value α (seismometer 20*,
The output of any of the seismometers 20b exceeds α, and the seismometer 20a
, 20d exceeds α,
Alternatively, it is determined whether a similar situation exists for the seismometer 0w-20z, and the turbine trip device 13 is controlled via the timer 30b or not via the timer 30b. The turbine trip device 13 can be manually operated via a manual turbine trip switch/S.

The reference figure is a characteristic diagram of the low frequency line cut filter r^ shown in Fig. 3, in which the vertical axis represents the sensitivity and the sea axis represents the vibration frequency. As shown in the figure, all shaft vibration signals with a frequency of /3Hz or higher are passed through (sensitivity 10064), but /,? Sensitivity decreases rapidly below Hz. For this reason, most of the shaft vibration signals below 3 Hz are blocked by the low frequency cut filter Is (the vibration frequency of an earthquake is often λ to 10 Hz), and the displacement display instrument and vibration recording instrument b And the vibration relay board 1/ is not reached much.

Next, the operation of the configuration example shown in FIG. 3 will be explained with reference to the explanatory diagram of the signal flow shown in FIG. The shaft vibration signal detected by the shaft vibration detector (block ioi) is converted into a signal after signal conversion and the low frequency component below /3Hz is cut (
block/Q), the displacement amount is displayed on the displacement amount display meter P-, and the vibration is recorded on the vibration recorder Pb (block tos
s, 1osb).

Next, the magnitude of the change is determined by the vibration relay board //, and when the displacement of a certain l bearing reaches the alarm value, [the house alarm system turns on (block 1oII, 1oz),
When the alarm value is not reached in either bearing (the F alarm device remains off).

iot). Also, the amount of displacement of a certain l bearing exceeds the trip value set to a value much larger than the alarm value (block 1
07), and if the displacement of any other bearing exceeds the alarm value (block 1017), then the displacement of a certain l bearing exceeds the backup trip value set to a value larger than the trip value. The presence or absence of a trip signal is determined after a predetermined time (block 10a) set by the timer 30m (block 101).
block/10a). Note that when the displacement amount does not reach the trip value or the backup trip value, the turbine trip device 13 does not operate (block ///a).

The predetermined time set by timer 3O island (block 1
When there is a trip signal on the ridge of (block/
io*), the turbine trip device 13 is turned on (block l/λ). Also, seismometer V Mushi ~, 2 (:11
Under the condition that the output of becomes a value greater than or equal to the set value α (
Block λ (113m, 203K, -〇≠),
The turbine trip device 13 is also turned on if the trip signal is present (block tto*) and also if the trip signal is present after the time set by the timer 30b (blocks 109b, /10b). (block saw). In addition, manual turbine trip switch l
It is also turned on by s (block//!, I/λ
).

Here, compared to the set time of timer 30m, timer 30b
The setup time is quite long. That is, the timer 30b is used to prevent the system from malfunctioning due to transient changes in signal waveforms or noise, and is generally set to several seconds. On the other hand, the timer 30b is used to stop the turbine trip function until the main vibration caused by the earthquake subsides, and is generally set to several minutes.

According to the conventional device as described above, when the amount of displacement of the turban shaft exceeds the trip value or backup trip value even though no large earthquake exceeding the set value α has occurred, the timer 30 with a short set time is activated. is activated and after a set time K) If there is an IJ knob signal, the turbine is tripped.

On the other hand, when an earthquake of a magnitude exceeding the set value α occurs and the amount of displacement of the turbine shaft exceeds the trip value or backup trip value, timer j0a with a short set time is activated first, and then it is determined whether or not there is a trip signal. is judged.

When there is a trip signal, the timer 30b with a long set time is activated and the automatic turbine trip function is stopped. In this way, to some extent, unnecessary tripping of the turbine due to earthquakes can be prevented. timer 3
When the set time of 0b has passed and the trip signal is still present even though the main vibration of the earthquake has subsided, and the amount of displacement of the shaft vibration exceeds the trip value (backup value), the turbine automatically switches off. Tried / pressed.

If the earthquake does not subside during the time set in timer j (7b) and timer 30b continues to operate, or until the time set in timer 30b elapses, the automatic turbine trip function will stop. Therefore, the operator uses the displacement display meter P.
a. Determine the υ operating condition using vibration recording and measurement, and manually trip the turbine.

In this way, the automatic turbine trip function is stopped for several minutes immediately after an earthquake occurs, eliminating the inconvenience of unnecessarily tripping the turbine. I try to make it so that I can have a bin trip in the evening.

[Problems with background technology]

However, operators must calculate the amount of absolute displacement by adding together the amount of change in whirling of the shaft during normal operation, the amount of seismic displacement at the vibration detector installation point, and the amount of displacement of the building and turbine generator installation stand during an earthquake. Since the judgment of whether or not the turbine should trip is made based on the displayed and recorded displacement indicator and vibration recorder, it may not be possible to make appropriate judgments and operate the turbine.

[Purpose of the invention]

The present invention has been made to overcome the above-mentioned drawbacks of the prior art, and provides an opportunity for an operator to accurately determine the amount of shaft vibration displacement of the turbine shaft when the automatic turbine earth lip function is stopped due to an earthquake. The purpose of the present invention is to provide a turbine protection device that enables proper manual operation (manual turbine trip).

[Summary of the invention]

In order to achieve the above object, the present invention provides an earthquake filter that cuts low-frequency shaft vibration components caused by an earthquake, and also detects the amount of displacement of the turbine shaft based on the shaft vibration signal obtained through this filter when an earthquake occurs. , display vibration,
The present invention provides a turbine monitoring device that prevents unnecessary turbine trips from being made manually by providing a displacement indicator, a vibration recorder, etc. for recording.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 7 and FIGS. 6 to 6 of the accompanying drawings. FIG. 6 is a configuration diagram of the same embodiment. When the output of either seismometer 20II or 20b exceeds the set value α, and the output of either seismometer 10c or 20d exceeds the set value α, and the seismometer 20W
When a similar relationship holds true for -20Z, relays J are activated via earthquake vibration relay board K1. In this way, multiple seismometers are installed, and each
D. The reason for using OR logic is to prevent the protection device from malfunctioning due to malfunction of some seismometers.

The relay turns on and off 4La of the earthquake filter switch 23 to connect or disconnect the earthquake filter tb in parallel to the low frequency cut filter fa on the output side of the turbine monitoring panel 7. The earthquake filter rb has better sensitivity than the low frequency cut filter fa and cuts even higher frequency components, and its characteristics are shown in FIG. As is clear from FIG. 7, the earthquake filter tb does not allow low frequency components of frequency 37 or lower to pass through. The shaft vibration signal that has passed through the earthquake filter tb is displayed and recorded by the displacement display meter C1 and the vibration recorder d, and is provided for reference for monitoring and control by the operator.

Relay J switches the contacts of changeover switch B so that timer 3Ob is activated when an earthquake greater than the set value α occurs. In addition, the vibration relay board // energizes the relay Kokukarasu via the timer 3O, switches the automatic turbine trip switch j/a, and at the same time, the timer 30
Activate b. Timer 30b is relay 29
Activate automatic turbine trip switch J/b via b. The turbine trip device 13 is operated by the automatic turbine trip switch 3/31b and the manual turbine trip switch 3 to trip the turbine.

Next, the operation of the embodiment shown in FIG. 6 will be explained in the following three cases with reference to the explanatory diagram of the signal flow shown in FIG. The first case is a case where no earthquake of a magnitude exceeding the set value α occurs, and the fourth case is a case where a major earthquake of a scale exceeding the set value α occurs.

In the first case above, the seismometer koO~,'10 d,
Since the output of 20w to 20z does not reach the set value α, relay n will not operate (even if some seismometers malfunction, as shown in Figure 4 (AND and OR logic is formed, relay n will not operate). only the low frequency cut filter t- is connected to the output side of the turbine monitoring panel 7 (blocks 203m, 203b).

λG Karasu, KoQ≠b,,zOta) Q-axis vibration detector ta~
The shaft vibration signal (block 204) detected by tn is converted into a signal by the turbine monitoring panel 7, and then sent to the displacement display meter and vibration recorder b via the low frequency cut filter rh, where it is displayed and displayed. At the same time as the recording is made (block 207 insect, ko 07b), the vibration relay board ll
is given to determine the size.

Among the displacements of the bearings detected by the shaft vibration detectors t, -tn, if the displacement of a certain l bearing exceeds the alarm value, the alarm device is turned on, and the displacement of any bearing is set to the alarm value. , the alarm device is turned off (Block Or, 209 m, λ0Pb).

When the detected displacement amount does not reach the trip value or does not reach the backup trip value, the turbine trip device 13 does not operate (block controller 10a
, λ10b, ko//a), when the displacement of a certain l bearing exceeds a trip value that is greater than the alarm value, and the displacement of any other bearing exceeds the alarm Ili value, or the displacement of a certain l bearing When exceeds the backup trip value that is greater than the trip value, Mai (Block J/λ)K determines whether there is a trip signal after the set time t of timer 3Q (Block, 2/3.2/Hiro) But otherwise the automatic turbine trip switch 3/ is turned off (block 2/, 2).

λ/l&).

When there is a trip signal after the set time t of timer 3Oa, it is determined whether the changeover switch O is on or off (Block/≠, tip), but in this case, the output of the earthquake needle reaches the set value α. Since it is not connected, the changeover switch is turned off (pronounced λ/).

Therefore, the turbine trip device 13 is activated and the turbine is tripped.

In the first case, the seismometers 20a to 20d,
Since the output of 20z reaches the set value α, 2 relays are activated, and the seismic filter rb is connected to the output side of the turbine monitoring panel 7 in parallel with the low frequency cut filter t- (block 2 (H&, 03b) , λQlhλO≠b, koOri.

For this reason, the shaft vibration signal (block 206) has its low frequency components (below UHz) cut by the seismic filter rb, and is then applied to the displacement display meter Pa and the vibration recording needle Pd, where the displacement display and A vibration recording is made (block J078°-07d). Therefore, the operator monitors and controls the system while observing the amount of displacement after removing the effects of the earthquake.

On the other hand, the vibration relay board/l is equipped with a low frequency cut filter fa.
The shaft vibration signal that has passed through is given, and the same magnitude judgment as in the first case is made. If the displacement of a certain l bearing exceeds the trip value and the displacement of any other bearing exceeds the alarm value, a color will be displayed, and if the displacement of any one of the bearings exceeds the backup trip value (Blockco/, 2
), the alarm device is activated and the presence or absence of a trip signal is determined after the time (several seconds) set by the timer 30m (Block/j, λ/ri). If there is a trip signal, the changeover switch is already turned on (block 2/6b), so the timer 30b is activated (block 4Q). Then, after the set time (several minutes) of the timer 30b, the presence or absence of the trip signal is determined (block 44/). When there is a trip signal, the turbine trip device 13 is activated and the turbine is tripped (block 222), but when there is no trip signal, the turbine trip device 13 is not activated (block λ1).
lb).

In this way, the automatic turbine trip function is stopped during the time set by the timer 30b (during which time the main motion of the earthquake subsides), but during this period, the operator can use the displacement display meter C1 via the earthquake filter tb. The turbine trip device can be operated by manual turbine trip 3 while observing the displacement amount displayed and recorded on the vibration recorder d (block 3). If there is still a trip signal after the set time of timer 30b, the automatic turbine trip function is activated and the turbine is tripped. In addition, if the main motion of the earthquake continues even after the time set on timer 30b! Although timer 30b continues to operate,
During this time, the automatic turbine function does not work, and the operator must manually trip the turbine.

〔Effect of the invention〕

As described above, according to the present invention, an earthquake filter is provided that cuts low-frequency shaft vibration components caused by an earthquake, and when an earthquake occurs, the automatic turbine trip function is stopped, and the shaft vibration signal obtained through the earthquake filter is Since the amount of displacement is displayed and recorded based on the above, it is possible to obtain a turbine protection device that allows an operator to appropriately manually operate the turbine trip device.

Therefore, unnecessary turbine trips can be prevented from occurring when an earthquake occurs.

[Brief explanation of drawings]

Figure 1 is a front view of the vicinity of the turbine of a nuclear power plant.
Figure 1 is a sectional view of the bearing part in Figure 7, Figure 3 is a configuration diagram of an example of a conventional device, Figure 1 is a characteristic diagram of the low frequency cut filter in Figure 3, and Figure 1 is a diagram of the low frequency cut filter in Figure 3. An explanatory diagram of the operation of the configuration example, FIG. 6 is a configuration diagram of an embodiment of the present invention, FIG. 7 is a characteristic diagram of the earthquake filter shown in FIG. 4, and FIG. It is an explanatory diagram of operation of a KM example. Turbine generator s foundation for l, λ#~Jm-returbine,
3...N', p...Turbine shaft, 6...Bearing,
U, $, Ko9mushi, Koqb... Relay, O... Earthquake filter switch, Easy... Changeover switch, J/a, J
/b...Automatic turbine trip switch, 3J...
Manual turbine trip switch. Application Substitute Kiyoshi Inomata (/f) Dimensions

Claims (1)

[Claims] / A shaft vibration detector that detects vibrations of a turbine shaft and outputs a shaft vibration signal; An earthquake filter that cuts only low frequency components of the shaft vibration signal; Furthermore, a low frequency cut filter that cuts only low frequency components, and when the output of a seismometer installed in the plant is above a predetermined value, the low frequency cut filter and seismic filter are connected in parallel to the output side of the shaft vibration detector. an earthquake filter switch that connects to the low frequency cut filter and connects only the low frequency cut filter when the frequency is below a predetermined value; a determination control means for determining whether or not there is a vibration and outputting a trip signal; a display recording means for recording; a timer for setting a manual operation period of a certain time width when the output of the seismograph is equal to or higher than the predetermined value or when the trip signal is given; a turbine trip device capable of tripping the turbine based on the output of the judgment control means, and capable of tripping the turbine only based on manual operation human power during the manual operation period, Turbine protector to protect against conditions. The turbine according to claim 1, wherein the display/recording means displays the displacement amount of the turbine shaft based on the shaft vibration signal provided through the low-frequency cut filter and records the vibration. Protective device.