JP2003028076A - Pump abnormality diagnosis device - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a pump abnormality diagnosis device that can determine abnormality of an electric motor or a transmission system that drives a pump, and can surely detect performance degradation or abnormality of the pump. It is in. According to the present invention, a process value including a suction pressure Ps, a discharge pressure Pd, and a discharge flow rate Q of a pump 30 is detected and added to a process value calculation unit 43. Process value calculation unit 4
Numeral 3 determines the total pump head by calculation, and also calculates the motor current of the AC motor 31 from at least the pump shaft power obtained from the process value of the pump and the power supply voltage of the AC power supply 33. The abnormality determination unit 44 diagnoses an abnormality based on the current detection value, the current deviation of the calculated current value obtained by the calculation, the predetermined total head design value, and the magnitude of the total head deviation of the calculated total head value obtained by the calculation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump abnormality diagnosing device for diagnosing a performance deterioration or abnormality of a pump used in a power plant such as a thermal power plant.

[0002]

2. Description of the Related Art First, a pump which is an object of abnormality diagnosis according to the present invention will be described with reference to a thermal power plant shown in FIG.

In FIG. 10, the steam generated in the boiler 1 passes through the steam control valve 2, works in the high-pressure turbine 3 and supplies a part of it to the high-pressure feed water heater 4, and then is heated again in the boiler 1 to intercept the intercept valve. 5, intermediate pressure turbine 6,
It works in the low-pressure turbine 7, a part of which is supplied to the deaerator 8 and the low-pressure feed water heater 9, and then flows to the condenser 10.

The steam flowing into the condenser 10 is heat-exchanged with the seawater supplied from the circulating water pump 11 to become condensed water, which accumulates in the hot well portion 12 of the condenser 10. The circulating water pump 1 keeps the seawater flow rate constant at the inlet / outlet temperature difference of the condenser 10.
It is controlled by one movable wing. Further, the water level of the hot well section 12 is controlled to a preset water level, and when the water level drops, makeup water is supplied to the condenser 11 through the water level control valve 13. Make-up water pump 14 when the water level drops significantly
Will start.

The condensate of the hot well section 12 is the condensate pump 1
5 and the condensate booster pump 16 supply the deaerator 8 via the low-pressure feed water heater 9. Also, the low pressure feed water heater 9
Condensate cools the extracted air guided to the above and becomes a drain, which collects in the drain cooler portion of the low-pressure feed water heater 9. This drain is sent from the drain pump 18 through the water level control valve 19 to the condensate pipe, merges with the condensate, and is sent to the deaerator 8. At this time, the condensate flow rate is controlled by the deaerator water level control valve 17, and the drain flow rate of the low pressure feed water heater 9 is controlled by the drain tank water level control valve 19.

The condensate fed to the deaerator 8 is supplied to the boiler 1 as feed water via the high-pressure feed water heater 4 by the feed water booster pump 20 and the feed water pump 21. The water supply flow rate is controlled by the water supply flow rate control valve 28.

FIG. 11 shows a structural sectional view of a horizontal shaft single-suction single-stage centrifugal pump generally used in a thermal power plant having such a structure.

In FIG. 11, the horizontal shaft single-suction single-stage centrifugal pump mainly includes a casing 51 surrounding the impeller 50 and a main shaft 5.
It is composed of a ball bearing 53 that supports 2 and a bearing cover 54, a shaft coupling (coupling) 55 for connecting to the electric motor 31, and an electric motor 31 for driving the pump.

Reference numeral 56 is a liner ring for preventing the pressurized water discharged from the impeller 50 from bypassing to the suction side. 57 is a gland packing for preventing water leakage from the gap between the main shaft 52 and the casing 51.
A packing 57 is provided between the main shaft 52 and the casing 51.

Water (fluid) enters the impeller 50 from the suction port 58, is pushed out to the outer periphery by the rotation of the impeller 50, is collected by the casing 51, and is discharged from the upper discharge port 59. The water receives the energy (total head) required to lift the water from the impeller 50.

By the way, when such a centrifugal pump is operated for a long period of time, it is inevitable that its performance will be deteriorated or it will be broken like other machines. The contents are as follows. (1) Due to the increased clearance between the liner ring and the casing,
Volume loss increases. (2) Rust and scale are attached to the impeller to increase friction loss. (3) The prescribed amount of water decreases due to the damage of the impeller. (4) The lubricating oil deteriorates. (5) The axes of the pump and motor are misaligned. (6) The efficiency of the motor decreases due to the resistance loss of the armature / main winding, the resistance loss of the excitation circuit, the brush loss, and the like. (7) The rotation speed increases due to the abnormality of the motor.

[0012] Such deterioration in performance or failure appears as changes in the pump discharge pressure, discharge flow rate, shaft power, shaft vibration, bearing oil temperature, bearing metal temperature. Therefore, in the central control room of the power plant, an alarm monitoring system is installed to monitor these process values, and when an abnormality occurs, an alarm is issued and the pump is stopped in an emergency that leads to a pump failure. I am trying.

Further, at the site where the pump is installed, the following inspections are carried out every day in an effort to detect the deterioration of the pump performance and the early detection of an abnormal condition. (1) Check the total pump head from the reading on the gauge attached to the pump (2) Check the current value with an ammeter (3) Check the voltage with a voltmeter (4) Pump, motor bearing, shaft with a tentacle or thermometer Check the temperature of the seal (5) Check for abnormal sound by hearing sound (6) Check for vibration by tentacles or vibrometer (7) Visually check for water leaks in the shaft seal (8) Visually check the amount of lubricant and dirt

On the other hand, in Japanese Patent Application Laid-Open No. 08-075617, the motor current value is monitored when the pump is operating at a constant rotation speed, and this motor current value exceeds a preset lower limit value. A pump failure diagnosis method is disclosed that sometimes outputs a failure alarm.

[0015]

The prior art requires the know-how and experience of a skilled operator who can determine the performance deterioration and abnormal state of the pump from the monitored process value, and the operator's judgment error is taken into consideration. However, there is a problem that the pump performance is deteriorated and the detection of abnormality is delayed.

Further, when the pump failure diagnosis method as described in Japanese Patent Application Laid-Open No. 08-075617 is applied to a pump of a power plant whose flow rate is controlled to be constant such as condensate water or water supply, In the case where an abnormality occurs in the bearing or packing, the required power increases due to the increase in frictional resistance, and the current value also increases. Therefore, there is a problem that it is not possible to judge the deterioration of the pump performance only by the decrease of the current value.

An object of the present invention is to provide a pump abnormality diagnosing device capable of discriminating an abnormality in an electric motor for driving a pump or a transmission system and surely detecting performance deterioration or abnormality of the pump.

[0018]

A feature of the present invention is that a process total value including a suction pressure, a discharge pressure, and a discharge flow rate of a pump is detected to calculate a total pump head, and at least a process value of the pump is calculated. The motor current of the AC motor is calculated from the pump shaft power and the power supply voltage calculated from the above, and the current deviation between the current detection value and the calculated current calculated by the calculation and the total lift determined in advance and the total lift calculated The purpose is to make an abnormality diagnosis based on the magnitude of the total head deviation of the calculated values.

According to the present invention, an abnormality diagnosis is made based on the detected current value, the current deviation of the calculated current value calculated by calculation, the predetermined total lift design value, and the size of the total lift deviation of the calculated total lift calculated value. Therefore, the abnormality of the electric motor for driving the pump and the abnormality of the transmission system can be discriminated and detected, and the deterioration or abnormality of the performance of the pump can be surely detected.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, the pump 30 is mechanically connected to an induction motor (AC motor) 31 via a shaft coupling 55. The induction motor 31 is connected to an AC power supply 33 via a breaker 32, and is supplied with an AC voltage from the AC power supply 33. The power supply voltage V of the AC power supply 33 is detected by the voltage detector 38, and the current (motor current) I flowing through the induction motor 31 is detected by the current detector 3.
9 detected.

The pump 30 is a centrifugal pump as shown in FIG. 11, and has a flow rate detector 34 and a pressure detector 3 at the outlet pipe 49.
5. A temperature detector 36 is installed, and a pressure detector 37 is installed in the inlet pipe 48.

The discharge flow rate Q detected by the flow rate detector 34, the discharge pressure Pd detected by the pressure detector 35, and the temperature detector 36.
The central processing unit (computer) 4 determines the fluid temperature T detected in step S1, the suction pressure Ps detected by the pressure detector 37, the power supply voltage of the voltage detector 38 and the current detection value I of the current detector 39.
5 is input to the process input unit 40.

These process values input to the process input section 40 are converted into units of pressure, m, flow rate, m ³ / min, temperature, ° C, current, A, and voltage, V. .
All the process values unit-converted by the process input unit 40 are taken into the averaging processing unit 41. Averaging processor 4
1 calculates the average value by filtering the process value.

The process value (average value) output from the averaging processor 41 is added to the process value calculator 43, and the discharge flow rate Q is added to the design value storage 42. The process value calculation unit 43 inputs the process value output from the averaging unit 41 and the design value stored in the design value storage unit 42 to obtain the current deviation ΔI and the total head deviation ΔH by calculation, and the abnormality determination unit 44. Add to. The abnormality determination unit 44 performs a failure diagnosis based on the current deviation ΔI and the total head deviation ΔH and outputs it to the output device 46.

FIG. 2 shows an example detailed configuration diagram of the design value storage unit 42 and the process value calculation unit 43. In FIG. 2, the fluid specific weight calculation unit 71 inputs the fluid temperature T from the averaging processing unit 41, obtains the fluid specific weight γ, and supplies it to the shaft power calculation unit 73.
The total head calculation unit 72 receives the discharge flow rate Q from the averaging processing unit 41,
The discharge pressure Pd and the suction pressure Ps are input, and the pipe diameter Ds of the suction pipe 48, the pipe diameter Dd of the discharge pipe 49, and the measurement point height difference h are input from the constant setting unit 80 of the design value storage unit 42.
Is input and the total head Hc is calculated.

The shaft power calculation unit 73 inputs the fluid specific weight γ, the discharge flow rate Q, the total head Hc, and the pump efficiency η _p from the pump efficiency function unit 81 of the design value storage unit 42, and inputs the pump efficiency η _p.
The shaft power L _{p of} 0 is calculated. The motor output calculation unit 74 inputs the motor shaft efficiency L _p and the motor efficiency η _m from the motor efficiency function unit 82 of the design value storage unit 42 to obtain the motor output L _m and apply it to the current calculation unit 75.

The current calculation unit 75 inputs the motor efficiency η _m , the power source voltage V from the averaging processing unit 41, and the motor power factor Pf from the motor power factor function unit 84 of the design value storage unit 42 to input the calculated current value of the motor current. Ic is calculated and applied to the current deviation calculator 76.

The current deviation computing unit 76 obtains the current deviation ΔI between the detected current value I and the calculated current value Ic from the averaging processing unit 41 and supplies it to the abnormality judging unit 44. Further, the total head deviation calculation unit 77 obtains the total head deviation ΔH of the total head design value Hd from the total head calculation value Hc calculated by the total head calculation unit 72 and the pump total head function unit 83 of the design value storage unit 42, and is abnormal. It is given to the determination unit 44.

The constant setting section 80 of the design value storage section 42 has
Pipe diameter Ds of suction pipe 48 and discharge pipe 49 shown in FIG.
Design values for the pipe diameter Dd and the measurement point height difference h are set. Pump efficiency function unit 81 and pump total head function unit 8
3 shows the pump efficiency η _p and the total head design value Hd of the characteristic curve as shown in FIG. 4 submitted by the manufacturer of the pump and the electric motor.
Is stored. The pump efficiency function unit 81 and the pump total head function unit 83 receive the discharge flow rate Q from the averaging processing unit 41, and output the pump efficiency η _p and the total head design value Hd according to the discharge flow rate Q.

The pump characteristic curve shown in FIG.
The example of the condensate pump of a 00 MW class power plant is shown.

The motor efficiency function section 82 and the motor power factor function section 84 store the characteristic curves of the motor efficiency η _m and the motor power factor Pf shown in FIG. 5, and the pump calculated by the shaft power calculation section 73 is stored. The motor efficiency η _m and the motor power factor _P f corresponding to the shaft power L _p are output.

Next, the operation will be described. Discharge flow rate Q detected by the flow rate detector 34, discharge pressure Pd detected by the pressure detector 35, fluid temperature T detected by the temperature detector 36, suction pressure Ps detected by the pressure detector 37, power supply of the voltage detector 38 The detected current value I of the voltage and current detector 39 is input to the process input section 40 of the central processing unit (computer) 45.

These process values input to the process input section 40 are converted into units of pressure, m, flow rate, m ³ / min, temperature, ° C, current, A, and voltage, V. .
All the process values unit-converted by the process input unit 40 are taken into the averaging processing unit 41. Averaging processor 4
1 calculates the average value by filtering the process value.

The filtering process performed by the averaging unit 41 is to integrate process values for a predetermined time (sampling time) and calculate an average value of the sampling time, which is obtained by the equation (1).

[0036]

[Equation 1]

All the process values filtered by the averaging processing unit 41 are fetched by the process value calculating unit 43. The discharge flow rate Q is also taken into the design value storage unit 42 and is used to retrieve the pump design value.

Now, the total head calculation unit 72 of the process value calculation unit 43 receives the discharge flow rate Q and the discharge pressure P from the averaging processing unit 41.
d, the suction pressure Ps, and the design value storage unit 42
From the constant setting section 80, the pipe diameter Ds of the suction pipe 48, the pipe diameter Dd of the discharge pipe 49 and the height difference h of the measuring point are input, and the total head Hc is calculated by the equation (2).

[0039]

[Equation 2]

The shaft power calculation unit 73 inputs the fluid specific weight γ, the discharge flow rate Q, the total head Hc, and the pump efficiency η _p from the pump efficiency function unit 81 of the design value storage unit 42 and inputs the pump efficiency η _{p according} to the formula (3). The axial power L _{p of} is calculated.

[0041]

[Equation 3]

The fluid specific weight γ has a constant value for a pump used where the variation range of the fluid temperature is small.
However, in the water supply pump of the power generation plant shown in FIG. 10, there are some which are used in the fluid temperature range of 30 ° C. to 180 ° C., and the variation range of the fluid specific weight γ becomes large. Therefore, it is necessary to accurately calculate the fluid specific weight γ.

As a result of various studies by the present inventor, the fluid temperature was
The fluid specific weight γ is determined by the approximation of the equation (4) in the range of 10 ° C to 200 ° C.

[0044]

[Equation 4] T: Fluid temperature (° C)

When the accuracy of the equation (4) was obtained from the steam table of the Japan Society of Mechanical Engineers, it was confirmed that the maximum deviation of the specific weight was 0.33%. According to the result confirmed by the present inventor, when the condensate pump having the performance shown in FIG. 4 is operated at the discharge flow rate of 13 m ³ / min, the deviation of the current value is about 0.35% even in the temperature region where the specific weight deviation is maximum. Is.

The motor output calculation unit 74 controls the pump shaft power L _p.
And the motor efficiency η _m from the motor efficiency function unit 82 of the design value storage unit 42 to obtain the motor output L _m and the current calculation unit 75.
Give to. The electric motor output L _m is obtained from the pump shaft power L _p and the electric motor efficiency η _m by the equation (5).

[0047]

[Equation 5]

A three-phase induction motor is used as the AC motor 31 for driving the pump 30 installed in the power generation plant, and the calculated current value Ic is obtained by the equation (6).

[0049]

[Equation 6]

The current calculation unit 75 inputs the motor efficiency η _m , the power supply voltage V from the averaging processing unit 41, and the motor power factor Pf from the motor power factor function unit 84 of the design value storage unit 42 to input the calculated current value of the motor current. Ic is calculated by the equation (6) and is given to the current deviation calculation unit 76.

The current deviation computing unit 76 obtains the current deviation ΔI between the detected current value I and the calculated current value Ic from the averaging processing unit 41 by the equation (7) and gives it to the abnormality judging unit 44. Further, the total head deviation calculation unit 77 calculates the total head calculation value Hc obtained by the total head calculation unit 72 and the total head deviation ΔH of the total head design value Hd from the pump total head function unit 83 of the design value storage unit 42 by the formula (8). ) And gives it to the abnormality determination unit 44.

The deviation .DELTA.H of the total head and the deviation .DELTA.I of the current value, which are used by the abnormality judging section 44 to judge the performance deterioration or the abnormality, are calculated by the equations (7) and (8).

[0053]

[Equation 7]

[0054]

[Equation 8]

The abnormality judging section 44 executes the abnormality diagnosis as follows based on the current deviation ΔI and the total head deviation ΔH.

The causes of pump performance deterioration and abnormality are roughly classified into three cases. (1) Abnormality of pump 30 (2) Abnormality of transmission system 55 (3) Abnormality of electric motor 31 (1) Abnormality of pump Mainly the following (a), (b) and (c) occur Then
As a result, it appears as a reduction in the total head. (a) Rust and scale adhere to the impeller, which increases friction loss and reduces the total head. (b) Due to the increased leakage from the liner ring,
Volume loss increases and total head decreases. (c) The breakage of the impeller reduces the theoretical head of the fluid that the impeller imposes on the fluid, thus reducing the total head.

The total head when the pump is abnormal will be described with reference to FIG.

As in the factors (a) and (b) described above, when the pressure loss and the volume loss of the pump operating at a constant rotational speed and a discharge flow rate of Q increase by ΔH, the total head is from H to H '. = H-Δ
Falls to H. In the case of factor (c), if the theoretical head of the pump given to the fluid decreases by ΔH, the total head is (a)
Similar to the case of (b), it decreases to H ′ = H−ΔH.

Taking the condensate booster pump 16 shown in FIG. 10 as an example, if the total head is lowered from H to H ', the flow rate Q is reduced unless the head loss from the pump outlet to the deaerator 8 is changed. Will be done. Therefore, the opening degree of the control valve 17 is increased and the head loss at the control valve 17 is reduced by ΔH to secure the flow rate Q. That is, the pump discharge pressure detector 35
The pressure Pd detected in step 1 decreases by ΔH, and the pump suction pressure Ps, discharge flow rate Q, and measurement point height difference h of other process values do not change. Therefore, the calculated total head Hc calculated by the equation (2) is Hd> Hc because Pd is decreased by ΔH as compared with the design total head Hd in the design value storage unit.

From the formula (3), the calculated value of the shaft power is ΔLp =
It decreases by (γ · ΔH · Q) / (6120 · η _p ), and the calculated current value Ic also decreases accordingly. However, the measured current value I is also lower than the calculated current value Ic because the total head is lowered, so that it is lower than when the pump is normal. Assuming that the decrease in pump efficiency ηp can be ignored, the relation between the calculated current value Ic and the measured current value I is Ic≈I.

If there is no valve for controlling the flow rate such as the regulating valve 17, the total head H is lowered to H ″ and the flow rate Q is lowered to Q ′. Also in this case, the relationship between the design total head Hd and the calculated total head Hc is Hd> Hc, and the current value is also Ic≈I.

(2) Abnormality in the transmission system When the pump efficiency is lowered to the extent that the rotational speed of the pump is not affected by the abnormality of the bearing or the shaft coupling such as the deterioration of the lubricating oil or the misalignment of the pump and the shaft center of the motor. Is the total pump head H
No change appears in the discharge flow rate Q. Since H and Q do not change, the calculated current value Ic does not change from the normal value. However, since the pump efficiency ηp actually decreases, the actually measured current value increases as the shaft power increases as shown in the equation (3). Therefore, the relationship between the total design head and the calculated total head is Hd = Hc, and the relationship between the calculated current value and the measured current value is Ic <I.

(3) Electric Motor Abnormality The electric motor abnormality includes overload and short circuit. In this case, there is a function of disconnecting the circuit breaker and stopping the motor by the operation of the protection relay that detects the abnormal state of the measured current value. However, the operation of the protection relay is the last means of motor protection, and it is necessary to detect the performance deterioration before the abnormal state in which the protection relay operates. Factors that reduce the performance of the motor include resistance loss of the armature and the main winding, resistance loss of the excitation circuit, and brush loss. If these losses increase, the efficiency of the motor decreases. In this case, since the rotation speed of the pump does not change, the relationship between the design total head and the calculated total head is Hd = Hc
Becomes Further, the relation between the calculated current value and the actually measured current value is Ic <I due to the decrease in motor efficiency.

When the number of revolutions increases for some reason, the relationship between the design total head and the calculated total head is Hd <Hc
When the number of rotations decreases, Hd> Hc.

From the above results, FIG. 7 shows a logic for determining the deterioration or abnormality of the pump performance. Deviation ΔH between design total head and calculated total head or deviation Δ between calculated current value and measured current value
By monitoring the amount of change in I, it is possible to detect performance deterioration or abnormality of the pump. In addition, there is also one that can determine the cause of pump performance deterioration or abnormality based on a combination of changes in ΔH and ΔI.

The threshold value for determining the performance deterioration due to ΔH is α
1, the threshold of abnormality is α2. The threshold value for determining the performance deterioration due to ΔI is β1, and the abnormality threshold value is β2. Since the performance decline is the reduction of the total head, "ΔH>α1"
In the case of (comparison result 65), it is determined that "the total head is slightly lowered", and the message 72 "The pump performance is slightly lowered" is output to the output device 46. In the case of "ΔH>α2" (comparison result 66), it is determined that "the total head is abnormally lowered", and the message 73 "The pump performance is abnormally degraded" is output to the output device 46.

The case where the total operating head is larger than the design total head is when the rotational speed of the pump increases. Therefore, in the case of “ΔH <−α1” (comparison result 67), it is determined that “total head is slightly increased”, and the message 74 is output to the output device 46, “the rotational speed of the motor is slightly increased”. When "ΔH <-α2" 68, "Total head is abnormally increased"
Then, a message 75 is output to the output device 46, stating that “the number of rotations of the motor is abnormally increased”.

When the transmission efficiency is lowered due to an abnormality in the transmission system such as the bearing or the shaft coupling 55, or when the motor efficiency is lowered due to an abnormality in the electric motor 31, the performance is judged to be normal or the total head is "normal". ΔH ≦ α1 ”(comparison result 69) and the current value is slightly increased“ ΔI> β1 ”(comparison result 70)
And the output device 46 outputs a message 76 that "the transmission efficiency or the motor efficiency is slightly reduced".

Further, it is determined that the total head is normal, "ΔH≤α
1 ”(comparison result 69) and the judgment that the current value has abnormally increased“ ΔI> β2 ”(comparison result 71) are satisfied by the AND condition,
A message 77 is output to the output device 46, "Transmission efficiency or motor efficiency is abnormally reduced."

The abnormality diagnosis is performed as described above. The current deviation between the detected current value and the calculated current value calculated by calculation, the total head design value determined in advance, and the total head deviation calculated by the calculation Since the abnormality diagnosis is performed based on the size of the pump, it becomes possible to determine and detect the abnormality of the electric motor or the transmission system that drives the pump, and it is possible to reliably detect the performance deterioration or abnormality of the pump.

8 and 9 show another embodiment of the present invention.

A detector installed in the power plant (pressure,
Flow rate, temperature, etc.) are not generally installed at the inlet and outlet of each pump, but are installed at the equipment and piping as shown in the power plant of FIG. Therefore, in the embodiment of FIG. 1, it is necessary to newly install a pressure detector and a flow rate detector at the inlet and outlet of the pump.

In the embodiment shown in FIGS. 8 and 9, in order to reduce the cost, the conventional detector is used.

A condenser pressure detector 22 is attached to the suction side of the condensate pump 10, a temperature detector 23 is attached to the condenser hot well, and a pressure detector 24 is attached to the inlet of the condenser booster pump on the discharge side and an outlet is attached to the discharge side. A flow rate detector 25 is attached to the.

The output signals of the detectors 22, 23 and 24 are input to the process input section 40 of the central processing unit (pump diagnostic device) 45. Assuming that the pressure detected by the pressure detector 22 is Pa, the pump suction pressure Ps is obtained by the equation (9). Further, when the pressure detected by the pressure detector 24 is Pb, the pump discharge pressure is obtained by the equation (10). Flow rate detector 25 The detected flow rate Qd is the condensate pump 15 (A,
B) It is the total flow rate of two units, and it is necessary to calculate the flow rate per unit. Therefore, since the performances of the condensate pumps A and B are almost the same, when the signals (on / off signals) M1 and M2 during pump operation are output with the circuit breakers 60 and 61 closed, the flow rate per unit is calculated by It is calculated in (11).

[0076]

[Equation 9]

[0077]

[Equation 10]

[0078]

[Equation 11]

Since the hot well temperature T hardly changes even at the inlet of the condensate pump, it can be used as it is in the process value calculation unit 43.

The power supply voltage V and the motor current I are omitted in the embodiments of FIGS.

As described above, the suction pressure calculation unit 90, the discharge flow rate calculation unit 91, and the discharge pressure calculation unit 92 which execute the calculation of the equations (9), (10) and (11) in the process value calculation unit 43.
In addition, the friction loss coefficients f1 and f2 of the piping and the actual lift h between the pressure detection point and the pump inlet / outlet port h are added to the design value storage unit 42.
By adding constant setting units 86 and 87 for setting the constants of a and hb and the diameters Ds and Dd of the inlet and outlet pipes, it is possible to diagnose the performance deterioration and abnormality of the pump as in the embodiment of FIG.

In the case of the embodiment shown in FIGS. 8 and 9, since the process value detection point is far from the pump, the accuracy of ΔH and ΔI calculated by the arithmetic unit is lower than that of the embodiment shown in FIG.
Therefore, the threshold value α1 for determining the deterioration of the pump performance
It is desirable that β1 and β1 be larger than those in the embodiment of FIG.

[0083]

According to the present invention, the current deviation between the detected current value and the calculated current value calculated by calculation, the predetermined total head design value and the total head deviation calculated by the calculation of the total head deviation value are used. Since the abnormality diagnosis is performed, the abnormality of the electric motor for driving the pump or the abnormality of the transmission system can be discriminated and detected, and the deterioration or abnormality of the performance of the pump can be surely detected.

[Brief description of drawings]

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

FIG. 2 is a detailed configuration diagram of an example of a process value calculation unit and a design value storage unit in FIG.

FIG. 3 is an explanatory diagram of measurement of total pump head.

FIG. 4 is a characteristic diagram showing a characteristic curve of a pump.

FIG. 5 is a characteristic diagram showing a characteristic curve of an electric motor.

FIG. 6 is an explanatory diagram showing a total head when pump performance is deteriorated.

FIG. 7 is a logic diagram of an abnormality determination unit.

FIG. 8 is a configuration diagram showing another embodiment of the present invention.

9 is a configuration diagram showing another embodiment of the present invention with FIG. 8. FIG.

FIG. 10 is a system configuration diagram of an example of a thermal power plant.

FIG. 11 is a cross-sectional view showing a configuration of a horizontal shaft single-suction single-stage centrifugal pump.

[Explanation of symbols]

8 Deaerator, 12 Condenser Hotwell, 15 Condensate Pump, 16 Condenser Booster Pump, 17 Deaerator Water Level Control Valve, 22 Condenser Pressure Detector, 23 Condenser Hotwell Temperature Detector, 24 Condensate booster pump inlet pressure detector, 25 Condensate flow rate detector, 30 Volute pump, 31
AC motor, 32 circuit breaker, 33 AC power supply, 34
Pump discharge flow detector, 35 Pump discharge pressure detector,
36 pump fluid temperature detector, 37 pump inlet pressure detector, 38 voltage detector, 39 current detector, 42 design data storage unit, 43 process value calculation unit, 44 abnormality determination unit.

Claims (4)

[Claims] 1. An AC electric motor fed from an AC power source, a pump driven by the AC electric motor, a process value detecting means for detecting a process value including a suction pressure, a discharge pressure and a discharge flow rate of the pump, Voltage detection means for detecting the power supply voltage of the AC power supply, current detection means for detecting the motor current of the AC motor, total head calculation means for calculating the total head by inputting the process value of the pump, and at least the pump Of the pump shaft power obtained from the process value and the power supply voltage detected by the voltage detecting means, and calculating the electric current of the motor flowing through the AC electric motor, and the detected current value detected by the current detecting means. A current deviation calculating means for obtaining a current deviation of the calculated current value obtained by the current calculating means, a predetermined total head design value and the total head operating value A pump comprising: a total head deviation calculating means for obtaining a total head deviation of the total head calculated value obtained by the means; and an abnormality determining means for making an abnormality diagnosis based on the magnitudes of the current deviation and the total head deviation. Abnormality diagnosis device. 2. An alternating current motor supplied from an alternating current power source, a centrifugal pump connected to the alternating current motor via a coupling, and a process value including a suction pressure, a discharge pressure and a discharge flow rate of the centrifugal pump. Process value detection means, voltage detection means for detecting the power supply voltage of the AC power supply, current detection means for detecting the motor current of the AC electric motor, and at least suction pressure, discharge pressure and discharge flow rate of the centrifugal pump are input. Pump total head calculating means for calculating the total pump head, and at least the pump shaft power obtained from the process value of the centrifugal pump and the power supply voltage detected by the voltage detecting means are input to calculate the motor current flowing in the AC motor. Current calculation means, the current detection value detected by the current detection means and the current calculation value calculated by the current calculation means A current deviation calculating means for obtaining a current deviation, a total head deviation calculating means for obtaining a total head deviation between a predetermined total head design value and a total head calculated value obtained by the total head calculating means, the current deviation and the total head A pump abnormality diagnosing device comprising: an abnormality determining unit that inputs a deviation and compares the current deviation and the total head deviation with a predetermined threshold value to perform abnormality diagnosis. 3. An induction motor fed from an AC power source, a spiral pump connected to the induction motor via a transmission system including a shaft coupling, a suction pressure, a discharge pressure, a discharge flow rate and a fluid of the spiral pump. Process value detecting means for detecting a process value including temperature, voltage detecting means for detecting a power supply voltage of the AC power source, current detecting means for detecting a motor current of the induction motor, and at least suction pressure of the spiral pump, The total head calculation means for calculating the total pump head by inputting the discharge pressure and the discharge flow rate, and the spiral flow pump by inputting the total lift calculation value calculated by the discharge flow rate and the total lift calculation means and the fluid specific weight based on the fluid temperature. Shaft power calculation means for calculating the pump shaft power of, and at least the pump shaft power calculated by the shaft power calculation means and the power supply voltage detected by the voltage detection means. A current calculation means for calculating a motor current flowing in the force and the AC motor by the operation, the current deviation calculation means for calculating the current deviation of the current values calculated by the current detection value detected by said current detecting means and said current computing means,
Total head deviation calculation means for obtaining a total head deviation between a predetermined total head design value and a total head calculated value obtained by the total head calculation means, and inputting the current deviation and the total head deviation, the current deviation and the above A pump abnormality diagnosing device comprising: abnormality determining means for performing abnormality diagnosis by comparing a total head deviation with a predetermined threshold value. 4. An induction motor fed from an AC power source, a spiral pump connected to the induction motor via a transmission system including a shaft coupling, a suction pressure, a discharge pressure, a discharge flow rate and a fluid of the spiral pump. Process value detecting means for detecting a process value including temperature, voltage detecting means for detecting a power supply voltage of the AC power source, current detecting means for detecting a motor current of the induction motor, and at least suction pressure of the spiral pump, Total head calculation means for calculating the total pump head by inputting the discharge pressure and discharge flow rate, and fluid specific weight calculation means for calculating the fluid specific weight based on the fluid temperature by inputting the fluid temperature, and the discharge flow rate and total head calculation Shaft power calculation means for determining the pump shaft power of the centrifugal pump by inputting the total head calculation value obtained by the means, the fluid specific weight, and the pump efficiency; A current calculation means for calculating a motor current flowing through the induction motor by inputting a motor output obtained based on shaft power and a power supply voltage detected by the voltage detection means, a current detection value detected by the current detection means, and the above A current deviation calculating means for obtaining the current deviation of the calculated current value obtained by the current calculating means, and a total head deviation calculation for obtaining a total head deviation of the predetermined total head design value and the total head calculation value obtained by the total head calculating means. Means for inputting the current deviation and the total head deviation, and comparing the current deviation and the total head deviation with a predetermined threshold value to perform abnormality diagnosis. Pump abnormality diagnosis device.