A method for diagnosing abnormal power output of a nuclear power steam turbine unit system

Abstract

The present invention belongs to the field of nuclear power, and specifically relates to a method for diagnosing abnormal power output in a nuclear power steam turbine unit system. The method comprises the following steps: Step 1: Overall unit performance analysis; Step 2: Comparative analysis of measurement point history; Step 3: Comparative analysis between loops; Step 4: Comparative analysis between measurement points; Step 5: Comparative analysis between systems; Step 6: Comparative analysis between units; and Step 7: Diagnosing and troubleshooting unit mechanical efficiency. This method can be used to diagnose abnormalities in the unit's power output based on the unit's current operating status, providing guidance for assessing the unit's power output and controlling reactor power.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear power, and in particular relates to a method for diagnosing abnormal electric power output of a nuclear power steam turbine unit system. Background Art

[0002] Nuclear power steam turbine generator systems utilize a control mode in which the reactor thermal power follows the turbine's power generation output. Once the turbine's target power is set, the reactor thermal power is adjusted to that target power. The turbine's output power depends on many factors, including reactor thermal power, seawater temperature, system efficiency, and instrument accuracy. Therefore, its output power is not a constant value. Therefore, when the nuclear power unit is operating at actual power, it is difficult for power plant operators to determine whether the turbine system power is operating normally.

[0003] Currently, nuclear power plants generally control the units by comparing the displayed reactor thermal power with the maximum limit, ensuring that the steam turbine system's output power is generated according to the unit's actual capacity. However, the reactor power displayed in the main control room is calibrated based on the thermal power of the steam turbine system circuit. The reactor thermal power calculation formula is as follows:

[0004]

[0005] WSG i =(H vi -H ei )Q ei -(H vi -H pi )Q pi

[0006] Where:

[0007] n is the number of unit loops;

[0008] W is the reactor thermal power;

[0009] WSG i is the thermal power of each steam generator;

[0010] Wp is the thermal power supplied to the reactor coolant system by other heat sources except the core;

[0011] H vi is the steam generator outlet steam enthalpy of each loop;

[0012] H ei is the main feed water enthalpy for each loop;

[0013] Q ei The main feed water flow of each loop;

[0014] H pi , Qpi Respectively represent the blowdown enthalpy and blowdown flow rate of the steam generator of each loop;

[0015] From the formula, we can find that the main feed water enthalpy value H ei Affects the calculation of the unit's thermal power, and the main feed water enthalpy H ei The main feed water temperature T fi Therefore, the main feed water temperature T fi Finally, the nuclear power turbine power P e Output and reactor thermal power W. Main feed water temperature T fi The output is measured by the main feed water thermometer. When the main feed water thermometer drifts high, it will cause the actual thermal power W of the reactor to e Higher than the displayed thermal power W, the steam turbine generator set output electrical power P e Too high; when the main feed water thermometer is low, it will cause the actual thermal power of the reactor W e Lower than the displayed thermal power W, the steam turbine generator set output power P e Restricted.

[0016] Therefore, it is necessary to propose a method for diagnosing abnormal electric power output of a nuclear power steam turbine unit system to quickly diagnose whether the main feed water temperature has caused abnormal electric power output. Summary of the Invention

[0017] The object of the present invention is to provide a method for diagnosing abnormal electric power output of a nuclear power steam turbine unit system, which can quickly determine whether the main feed water temperature causes abnormal electric power output.

[0018] The technical solutions of the present invention are as follows:

[0019] The present invention is a method for diagnosing abnormal power output of a nuclear power steam turbine system, comprising the following steps:

[0020] Step 1: Overall performance analysis of the unit;

[0021] Step 2: Comparative analysis of the measurement point’s own history;

[0022] Step 3: Comparative analysis between loops;

[0023] Step 4: Comparative analysis between measurement points;

[0024] Step 5: Comparative analysis between systems;

[0025] Step 6: Comparative analysis between units;

[0026] Step 7: Diagnose and check the mechanical efficiency of the unit.

[0027] Preferably, in step 1, the electric power deviation limit ΔW is set at the same seawater temperature. e, Thermal efficiency deviation limit Δη e ;

[0028] If the current power W ei ,η ei If one of the following conditions is met, proceed to step 2:

[0029] |W ea -W ei |>ΔW e ,

[0030] |η ea -η ei |>Δη e ,

[0031] Where W ea is the historical average electric power at the seawater temperature, η ea is the historical average unit efficiency at this seawater temperature.

[0032] Preferably, in step 2, the main feed water temperature T of the unit is determined fi Accuracy limit; main feed water temperature T fi Maximum allowable deviation of accuracy ΔT e The calculation is as follows:

[0033] ΔT e =ΔT e1 +ΔT e2 ,

[0034] Where, ΔT e1 The allowable deviation within the accuracy grade of the temperature sensing primary element, ΔT e2 It is the allowable deviation within the accuracy grade of the temperature transmitter.

[0035] Preferably, in step 2, the historical average water supply temperature T of the same unit with similar power is compared. fa , if the current display main water temperature T fi If the following equation is satisfied, the temperature instrument calibration is performed; if not, proceed to step 3; after the temperature instrument calibration is completed, if the following equation is still satisfied, proceed to step 7.

[0036] |T fa -T fi |>ΔT e .

[0037] Preferably, in step 3, the main feed water temperature deviation limit ΔT between different loops of the same unit is determined L , calculate the main feed water temperature deviation displayed by each loop. If the following formula is satisfied, perform instrument calibration; if not, perform step 4; after completing the temperature instrument calibration, if the following formula is still satisfied, perform step 7.

[0038] max(T fi1 , T fi2 ,…,T fin )-min(T fi1 , T fi2 ,…,T fin )>ΔT L ,

[0039] Where, T fi1 , T fi2 , T fin is the main feed water temperature of each loop.

[0040] Preferably, in step 4, the current main water supply online instrument T is calculated F With the main feed water temperature T fi Temperature deviation ΔT at similar locations Fi ,

[0041] ΔT F =T F -T fi ,

[0042] Calculate historical temperature deviation ΔT F1 , ΔT F2 ,......,ΔT Fi-1 ,

[0043] If the following equation is satisfied, then perform the instrument calibration work; if it is not satisfied, then perform step five; after completing the temperature instrument calibration work, if the following equation is still satisfied, then perform step seven.

[0044] ΔT Fi >max(ΔT F1 , ΔT F2 ,…,ΔT Fi-1 ).

[0045] Preferably, in step 5, the outlet temperature of the high pressure feed water heater T is calculated. H With the main feed water temperature T fi Deviation ΔT Hi ,

[0046] ΔT H =T H -T fi ,

[0047] Calculate historical temperature deviation ΔT H1 , ΔT H2 , ΔT Hi-1 ,

[0048] If the following equation is satisfied, then perform the instrument calibration work; if it is not satisfied, then perform step 6; after completing the temperature instrument calibration work, if the following equation is still satisfied, then perform step 7.

[0049] ΔT Hi >max(ΔT H1 , ΔT H2 ,…,ΔT Hi-1 ).

[0050] Preferably, in step 6, the average main feed water temperature deviation limit ΔT of the same model unit under the same seawater temperature and the same power platform is determined. m , compare the historical average main feed water temperature T of the same model unit under the same seawater temperature and the same power platform m , if the current main feed water temperature T fi If the following equation is satisfied, perform the instrument calibration. If not, proceed to step 7.

[0051] |T m -T fi |>ΔT m .

[0052] Preferably, in step seven, the tightness of the boundary valves of the steam turbine unit system is diagnosed.

[0053] Preferably, in step seven, the efficiency diagnosis is performed on the heat exchanger of the steam turbine system and the efficiency diagnosis is performed on each cylinder of the steam turbine system.

[0054] The remarkable effects of the present invention are:

[0055] (1) This method can be used to diagnose whether the unit's electrical power output is abnormal based on the current unit's operating status, providing guidance for evaluating the nuclear power unit's electrical power and controlling the reactor power.

[0056] (2) This method was verified on a domestic million-kilowatt nuclear power unit. On-site diagnosis using this method revealed that the main feed water thermometer displayed a deviation, which affected the power output.

[0057] (3) This method was used to diagnose abnormal power output for the above-mentioned unit, increasing the power output by nearly 5MW, which will generate approximately RMB 14 million in additional revenue per year. The overall effect of this method is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a schematic diagram of the abnormal power output diagnosis process of a nuclear power unit system. DETAILED DESCRIPTION

[0059] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] like Figure 1 As shown, the present invention is a method for diagnosing abnormal power output of a nuclear power steam turbine system, comprising the following implementation steps:

[0061] Step 1: Overall performance analysis of the unit

[0062] Set the electric power deviation limit ΔW at the same seawater temperature e , Thermal efficiency deviation limit Δη e ;

[0063] If the current power W ei ,η ei If one of the following conditions is met, proceed to step 2:

[0064] |W ea -W ei |>ΔW e ,

[0065] |η ea -η ei |>Δη e ,

[0066] Where W ea is the historical average electric power at the seawater temperature, η ea is the historical average unit efficiency at this seawater temperature.

[0067] Step 2: Comparative analysis of the measurement point's own history (historical data analysis)

[0068] Determine the unit's main feed water temperature T fi Accuracy limit, main feed water temperature T fi Maximum allowable deviation of accuracy ΔT e The calculation is as follows:

[0069] ΔT e =ΔT e1 +ΔT e2 ,

[0070] Where, ΔT e1 The allowable deviation within the accuracy grade of the temperature sensing primary element, ΔT e2 The allowable deviation within the accuracy grade of the temperature transmitter;

[0071] Compare the historical average feed water temperature T of the same unit under similar power fa , if the current display main water temperature T fi If the following equation is satisfied, the temperature instrument calibration is performed; if not, proceed to step 3; after the temperature instrument calibration is completed, if the following equation is still satisfied, proceed to step 7.

[0072] |T fa -T fi|>ΔT e .

[0073] Step 3: Inter-loop comparative analysis (inter-loop analysis)

[0074] Determine the main feed water deviation limit ΔT between different loops of the same unit L ,

[0075] Calculate the main feed water temperature deviation displayed by each loop. If the following formula is satisfied, perform the instrument calibration work; if not, proceed to step 4. After completing the temperature instrument calibration work, if the following formula is still satisfied, proceed to step 7.

[0076] max(T fi1 , T fi2 ,…,T fin )-min(T fi1 , T fi2 ,…,T fin )>ΔT L ,

[0077] Where, T fi1 , T fi2 , T fin is the main feed water temperature of each loop.

[0078] Step 4: Comparative analysis between measurement points (inter-measurement point analysis)

[0079] Calculate the current main water supply online instrument T F With the main feed water temperature T fi Temperature deviation ΔT at similar locations Fi ,

[0080] ΔT F =T F -T fi ,

[0081] Calculate historical temperature deviation ΔT F1 , ΔT F2 ,......,ΔT Fi-1 ,

[0082] If the following equation is satisfied, then perform the instrument calibration work; if it is not satisfied, then perform step five; after completing the temperature instrument calibration work, if the following equation is still satisfied, then perform step seven.

[0083] ΔT Fi >max(ΔT F1 , ΔT F2 ,…,ΔT Fi-1 ).

[0084] Step 5: Comparative Analysis between Systems (Inter-System Analysis)

[0085] Calculate the outlet temperature T of the high pressure feedwater heater H With the main feed water temperature T fi Deviation ΔT Hi ,

[0086] ΔT H =T H -T fi ,

[0087] Calculate historical temperature deviation ΔT H1 , ΔT H2 , ΔT Hi-1 ,

[0088] If the following equation is satisfied, then perform the instrument calibration work; if it is not satisfied, then perform step 6; after completing the temperature instrument calibration work, if the following equation is still satisfied, then perform step 7.

[0089] ΔT Hi >max(ΔT H1 , ΔT H2 ,…,ΔT Hi-1 ).

[0090] Step 6: Comparative Analysis between Units (Inter-Unit Analysis)

[0091] Determine the average main feed water temperature deviation limit ΔT for the same model unit at the same seawater temperature and the same power platform m , compare the historical average main feed water temperature T of the same model unit under the same seawater temperature and the same power platform m , if the current main feed water temperature T fi If the following equation is satisfied, perform the instrument calibration. If not, proceed to step 7.

[0092] |T m -T fi |>ΔT m .

[0093] Step 7: Diagnosis and troubleshooting of unit mechanical efficiency

[0094] Diagnose the tightness of the boundary valves of the steam turbine unit system, diagnose the efficiency of the heat exchanger of the steam turbine unit system, and diagnose the efficiency of each cylinder of the steam turbine unit.

[0095] This method was verified on a domestic million-kilowatt nuclear power unit. Using this method, on-site diagnosis revealed a deviation in the main feedwater temperature meter, which affected the power output. Based on the diagnostic results, the power output before and after the adjustment was as follows:

[0096]

[0097] Using this method, the abnormal power output of the unit was diagnosed, and the power output was increased by nearly 5MW, which will generate approximately 14 million yuan in additional revenue per year. The overall effect of this method is good.

[0098] The above shows and describes the basic principles, main features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be regarded as illustrative and non-restrictive in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and all variations that come within the meaning and range of equivalents of the claims are intended to be included therein.

[0099] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for diagnosing abnormal power output of a nuclear power steam turbine system, characterized by: The following steps are involved: Step 1: Overall performance analysis of the unit; Set the electric power deviation limit ΔW at the same seawater temperature e , Thermal efficiency deviation limit Δη e ; If the current power W ei 、Current unit efficiency η ei If one of the following conditions is met, proceed to step 2: |In ea -IN ei |>ΔW e , |the ea -or ei |>D e , Where W ea is the historical average electric power at the seawater temperature, η ea is the historical average unit efficiency at the seawater temperature; Step 2: Comparative analysis of the measurement point’s own history; Determine the unit's main feed water temperature T fi Accuracy limit; main feed water temperature T fi Maximum allowable deviation of accuracy ΔT e The calculation is as follows: ΔT e =ΔT e1 +ΔT e2 , Where, ΔT e1 The allowable deviation within the accuracy grade of the temperature sensing primary element, ΔT e2 The allowable deviation within the accuracy grade of the temperature transmitter; Compare the historical average feed water temperature T of the same unit under similar power fa , if the current display main water temperature T fi If the following equation is satisfied, the temperature instrument calibration is performed; if not, proceed to step 3; after the temperature instrument calibration is completed, if the following equation is still satisfied, proceed to step 7. |T fa -T fi |>ΔT e ; Step 3: Comparative analysis between loops; Determine the main feed water temperature deviation limit ΔT between different loops of the same unit L , calculate the main feed water temperature deviation displayed by each loop. If the following formula is satisfied, perform instrument calibration; if not, perform step 4; after completing the temperature instrument calibration, if the following formula is still satisfied, perform step 7. max(T fi1 ,T fi2 ,…,T fin )-min(T fi1 ,T fi2 ,…,T fin )>ΔT L , Where, T fi1 , T fi2 , T fin is the main feed water temperature of each loop; Step 4: Comparative analysis between measurement points; Calculate the current main water supply online instrument T F With the main feed water temperature T fi Temperature deviation ΔT at similar locations Fi , ΔT F =T F -T fi , Calculate historical temperature deviation ΔT F1 , ΔT F2 ,……,ΔT Fi-1 , If the following equation is satisfied, then perform the instrument calibration work; if it is not satisfied, then perform step five; after completing the temperature instrument calibration work, if the following equation is still satisfied, then perform step seven. ΔT Fi >max(ΔT F1 ,ΔT F2 ,…,ΔT Fi-1 ); Step 5: Comparative analysis between systems; Calculate the outlet temperature T of the high pressure feedwater heater H With the main feed water temperature T fi Deviation ΔT Hi , ΔT H =T H -T fi , Calculate historical temperature deviation ΔT H1 , ΔT H2 , ΔT Hi-1 , If the following equation is satisfied, then perform the instrument calibration work; if it is not satisfied, then perform step 6; after completing the temperature instrument calibration work, if the following equation is still satisfied, then perform step 7. ΔT Hi >max(ΔT H1 ,ΔT H2 ,…,ΔT Hi-1 ); Step 6: Comparative analysis between units; Determine the average main feed water temperature deviation limit ΔT for the same model unit at the same seawater temperature and the same power platform m , compare the historical average main feed water temperature T of the same model unit under the same seawater temperature and the same power platform m , if the current main feed water temperature T fi If the following equation is satisfied, perform the instrument calibration. If not, proceed to step 7. |T m -T fi |>ΔT m ; Step 7: Diagnose and check the mechanical efficiency of the unit.

2. The method for diagnosing abnormal power output of a nuclear power steam turbine system according to claim 1, wherein: In the step seven, the tightness of the boundary valves of the steam turbine unit system is diagnosed.

3. The method for diagnosing abnormal power output of a nuclear power steam turbine system according to claim 2, wherein: In the step seven, the efficiency of the heat exchanger of the steam turbine system is diagnosed, and the efficiency of each cylinder of the steam turbine system is diagnosed.

Images