JPS6020751A - Monitor and protector for bearing of generator - Google Patents

Abstract

PURPOSE:To improve the reliability by operating a protecting circuit on the basis of the temperature and flow rate of coolant of a bearing as well as physical values affecting the influence to the temperature of the bearings. CONSTITUTION:The outputs of a rotating speed detector 11, a coolant temperature detector 12 a coolant flow rate detector 13 and a bearing temperature detector 6 are respectively inputted through converters 14, 16, 17, 15 to the primary differentiators 18, 20, 21, 19, the outputs are inputted through the secondary differentiators 22, 24, 25, 23 to an arithmetic circuit 27, and inputted to an arithmetic circuit 26. The outputs of the arithmetic circuits 26, 27, the output of the converter 15 and the output of the differentiator 19 are respectively compared by comparators 28, 29, and the logic product of the outputs is taken by an AND gate 30 to operate a protecting circuit 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a generator bearing monitoring and protection device that monitors the condition of a bearing metal of a generator and starts a protective operation when an abnormality is detected. 1. Conventionally, there was a device of this type shown in Figure 1.In the figure, tl+
is the generator, (21 is the rotating shaft of the generator, (3) is the bearing of the rotating shaft, (41 is the bearing metal of the bearing, +51
is a cooling water pipe for cooling the bearing (3), (6) is a detector that detects the temperature of the bearing metal (4), (7) is a converter that converts the output of the thermometer into an electrical signal, ]8) is a comparator,
(9) is the comparator (reference voltage source of 81, uO) is the protection circuit and must be low (,, 7a) is the output of the converter (7), (9a)
is the reference voltage value, (8a) is the output of the comparator (8), and (7
a) When <(9a), (8a) is logic “0”, (7a)
When ≧(9a), (8a) becomes logic “1”, and (
When 8a) becomes logic "1", the protection circuit (lO) is activated.

Since the conventional device is configured as described above, the reference voltage value (9a) is fixedly determined, and therefore the maximum allowable temperature of the bearing is fixedly determined, and other conditions related to the bearing are Therefore, it is not possible to set the maximum allowable temperature of the bearing to the most appropriate value, and the reference voltage value (9a)
If ffi is set to a high value, the detection of bearing abnormality will be delayed, while if the reference voltage value (9a) is set to a low value, the protection circuit (IO) may malfunction even though there is no abnormality in the bearing. There was a drawback that

This invention was made in order to eliminate the drawbacks of the more conventional ones mentioned above, and it detects various physical quantities that affect the temperature of the bearing, such as the temperature and flow rate of the bearing cooling water and the rotational speed of the shaft. , calculate the first and second derivatives of these physical terms and the temperature of the bearing with respect to time, determine the maximum allowable value of the bearing temperature from these derivatives, and determine the maximum allowable value of the bearing temperature from these second-order derivatives i & A highly reliable monitoring and protection device is provided by determining the maximum allowable temperature rise rate and activating the protection circuit when both the bearing groove a and its temperature rise rate exceed their respective maximum allowable values. It is intended to.

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

Figure 2 μ is a block diagram showing one embodiment of this invention;
The same symbols as in the figure indicate the same or equivalent parts, (11) is the rotation speed bearing, (12) is the cooling water temperature detector, (13)
are cooling water flow rate detectors, (14), (15,l,
(16) and (17) are the detectors (1υ, (6
), (12), and (13) into electrical signals, and in this specification, the detector (6) and the converter (
The combination 15) will be temporarily referred to as a bearing temperature converter, and each combination of (1υ and (14), (12) and (16), and (13) and (17) will be temporarily referred to as each converter. ( 18)
.

(19), (20), (2υ, (22), (
23), (24), and (25) are respectively differentiating circuits, (26) is a first arithmetic circuit, (27) is a second arithmetic circuit, (28) is a first comparator, and (29) is a first arithmetic circuit. Comparator 2, (30) is an AND gate.

Converter (1, (15), (16), (17)
The output of each is X□.

If X2, X3, and X4 are differentiator circuit (18
), (19).

(20,) , (2υ, (22) , (23)
The outputs of , (24) and (25) are respectively □.

λ2, λ3, λ4, λ1, 22 people 3. λ4, where k represents the first-order differential of the variable X with respect to time, and X represents the second-order differential of the variable X with respect to time.

Performance r4. After performing all the calculations, the calculation result Y is outputted as the first reference value. However, if Y exceeds X2max, XZma
Outputs X as the value of Y. Here, X2max is X2
This value is predetermined as the maximum allowable value of C11
depends on the degree to which Xi does not affect changes in bearing temperature.
With a predetermined coefficient! '%C1O is a value determined in advance by adding a margin to the current value of the bearing temperature.

Finished the performance? , and outputs the calculation result 2 as the second reference value. However, if 2 exceeds X2max, Xzm
axf: Output as the value of z. Here, XZmaX is a value predetermined as the maximum allowable value of 2, and
2 is a coefficient determined in advance depending on the degree to which Xl does not affect X2 (rate of change in bearing temperature), and C
20 is a value determined in advance by adding a margin to the current value of the rate of change of the bearing temperature. The values of Y and 2 are calculated every cycle of ΔT, and the values are held until the next calculation.

FIG. 3 is a diagram showing temporal changes in the output of the capacity converter during operation of the generator, and T indicates an appropriate time point after the start of operation. Fourth
The figure shows the temporal changes in X2 and Y and the temporal changes in C20 is determined, and the reference value Y to be used from T+ΔT to T+2ΔT,
This shows that Z is determined.

FIG. 5 is a diagram showing the difference in operation between the conventional monitoring and protection device and the device of the present invention. Between T X in T
2. l? Y, X2≧2 and the comparator (28), (
The output of the AND gate (30) becomes logic “1”.
) output is logic "1" and the 9 insurance circuit (10) operates, but in the conventional device (7a = X2) ≧ (9a)
Therefore, the protection circuit (lO) operates after T + △T, and the bearing may be damaged during this time.In order to avoid this, setting (9a) low will prevent the bearing in normal condition. There is a risk that the protection circuit (lO) may malfunction due to the temperature rise.

In addition, in the above embodiment, the rotational speed of the generator and the flow of cooling water are physical quantities that affect the temperature of the generator bearing.
(1) and water temperature are used; however, other physical quantities may be used, and vibration amplitude of the bearing, pressure, etc. may be used instead of the bearing temperature as the object of monitoring.As described above, this invention According to AiJ, in order for equipment abnormalities to progress and cause greater damage, AiJ can accurately detect the abnormalities and
Desired cough-keeping movements can be performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a conventional device, Fig. 2 is a project diagram showing an embodiment of the present invention, and Fig. 3 shows the temperature of the bearing and the physical changes that affect this temperature. Figure 4 corresponds to Figure 3 and shows the changes in X2 r Y e
FIG. 5 is a diagram showing temporal changes in X2 t Z, and FIG. 5 is a diagram showing abnormality detection by the apparatus of FIG. 2. fi+... Generator, (2)... Rotating shaft, (3)...
・Bearing, (5)...Cooling water pipe, 161, (15)
...Bearing temperature converter, (1υ, (14)...Rotation speed converter, (12), (16)...Cooling water temperature converter, (13). (17)...Cooling water amount Converter, (10)... Protection circuit, (1B). (19), (20), (21)... Negative differential circuit, (22), (23), (24), (25) )・−・Second order differential circuit, respectively.
(26)...first arithmetic circuit, (27)...second arithmetic circuit. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa Figure 3 Figure 4 Figure 5 Procedural amendment (voluntary) Mr. Commissioner of the Japan Patent Office 1. Indication of case: Japanese Patent Application No. 125706/1982 2. Title of invention: Generator bearing monitoring and protection device 3. Amendment Relationship with the case involving the person who filed the patent application Patent applicant address 2-02-3 Marunouchi, Chiyoda-ku, Tokyo Name
(601) Mitsubishi Electric Corporation Representative Hitoshi Katayama 4, Agent (1) "Detailed explanation of the invention" column of specification 1 (2) Same book, page 4, line 20, "It becomes X4." Correct "There is" to "Let it be X4." (3) In the same book, page 5, line 1, rXJ is written as r xi (
i = L2P314) Correct as J. (41 Ibid., page 5, line 1, rXJ and r Xl(i
-1+2+3+4) Correct it as j. (5) The same book, page 5, line 2, rXJ and r Xl (
i = 1.2, 3.4) Correct as J. (6) In the same book, page 5, line 10, the phrase ``Add the margin'' is corrected to read ``Add 1 margin.'' (7) In the same book, page 5, lines 19 and 20, the phrase "by adding margin" is corrected to "by margin value."(that's all)

Claims (1)

[Claims] A bearing temperature converter that converts the temperature of the generator bearing into an electrical signal, and physical variables that do not affect the temperature of the generator bearing, such as the temperature and flow rate of cooling water for the bearing and the rotation speed of the generator. into electrical signals, each -order differentiator circuit which differentiates the output of the bearing temperature converter and the output of each of the above converters with respect to time, and the output of each -order differentiator circuit is inputted. Each quadratic differential circuit that further differentiates the input of the lever with respect to time, the output of the bearing temperature converter, and the output of each upper Nd modulus differential circuit are input, predetermined calculations are performed, and the calculation results are used as the first reference value. A first arithmetic circuit that outputs an output as , the output of a first-order differential circuit that receives the output of the bearing temperature converter as input, and the output of each of the second-order differential circuits that are input, performs a predetermined calculation, and uses the calculation result as a second standard. a second arithmetic circuit that outputs the output as a value; and a means for activating a protective operation when a reference value for a generator bearing is exceeded.