Sodium-cooled fast reactor primary frequency modulation control method

Abstract

The invention belongs to the technical field of nuclear power equipment control, and particularly relates to a primary frequency modulation control method for a sodium-cooled fast reactor. Comprising the following steps: step 1, signals of a unit entering a primary frequency modulation control mode come from working conditions 1 and 2, a'OR 'relation is made between the working conditions 1 and 2, and the unit enters the primary frequency modulation control mode as long as one of the working conditions 1 and 2 is met; 2, signals of the unit quitting the primary frequency modulation control mode come from the working conditions of the conditions 1-13, an OR relation is made between the signals, and the unit quits the primary frequency modulation control mode as long as one of the conditions 1-13 is met. The method has the advantages that the primary frequency modulation control technology can quickly respond to power grid frequency changes, the stability of the power grid frequency is maintained by automatically adjusting the active power of the generator set, the power grid pressure is relieved, and the overall operation quality of the power grid is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear power equipment control, and particularly relates to a primary frequency modulation control method for a sodium-cooled fast reactor. Background Art

[0002] To ensure the stable operation of the power grid, dynamically balance the power of the power grid, and cope with various changes and interferences, through the primary frequency modulation technology, it is necessary to adapt to the needs of external load changes, thereby reducing the amplitude of the power grid frequency change and maintaining the stability of the power grid frequency.

[0003] The original sodium-cooled fast reactor unit was in the turbine following reactor mode, and it was difficult for the unit to achieve the primary frequency modulation function. Summary of the Invention

[0004] The purpose of the present invention is to provide a primary frequency modulation control method for a sodium-cooled fast reactor, which can maintain the frequency stability of the power system. When the frequency of the power grid deviates from the rated value, the primary frequency modulation can automatically control the power output of the generator set to limit the change of the power grid frequency and ensure that the power grid frequency remains in a stable state.

[0005] The technical solution of the present invention is as follows: A primary frequency modulation control method for a sodium-cooled fast reactor includes the following steps:

[0006] Step 1: The signals for the unit to enter the primary frequency modulation control mode come from operating conditions 1 and 2. An "OR" relationship is made between the two. As long as one of the conditions of operating conditions 1 and 2 is satisfied, the primary frequency modulation control mode is put into operation.

[0007] Step 2: The signals for the unit to exit the primary frequency modulation control mode come from the operating conditions of conditions 1 to 13. An "OR" relationship is made between the signals. As long as one of the conditions 1 - 13 is satisfied, the primary frequency modulation control mode is exited.

[0008] The operating condition 1 in step 1: The measured pressure of the main steam header is greater than 12.8 MPa and less than 13.2 MPa; the sodium temperature in the primary loop is greater than 307 °C and less than 309 °C; and the sodium temperature in the secondary loop is greater than 307 °C and less than 309 °C; under the main steam pressure mode of the steam turbine and the difference between the measured speed value of the steam turbine and the set value is greater than 4 RPM; an "AND" gate is made between the above signals.

[0009] The operating condition 2 in step 1: The sodium temperature in the primary loop is greater than 307 °C and less than 309 °C; and the sodium temperature in the secondary loop is greater than 307 °C and less than 309 °C; under the main steam pressure mode of the steam turbine and the difference between the measured speed value of the steam turbine and the set value (3000 RPM) is less than -4 RPM; an "AND" gate is made between the signals of the above operating conditions 1 and 2.

[0010] The frequency modulation control mode in step 1 includes:

[0011] Control response logic 1: The set value of the steam turbine speed of the nuclear power plant unit is 3000 RPM. At the same time, the measured speed value of the steam turbine is received, and the difference between the two is calculated (the set value is +, and the measured value is -).

[0012] Control response logic 2: The operation signal enters the F(x)2 (-3 ≤ F(x)2 ≤ 3) module and is converted into a power signal.

[0013] Control response logic 3: The power signal enters the F(x)1 (-3 ≤ F(x)2 ≤ 3) module and is converted into an energy signal. The accumulated amount is used as the flow command of the high-pressure regulating valve of the steam turbine, and the valve opening is controlled through the flow command.

[0014] Control response logic 4: The command of the main feed water valve remains unchanged.

[0015] Control response logic 5: The measured pressure and the set pressure of the main steam header enter the PID controller for calculation, and the output speed signal is used to control the speed of the main feed water pump, so as to adjust the pressure of the main steam header to be stable at the original value;

[0016] Among them, the calculation formula adopted by the PID operation module is as follows:

[0017] G(s) = (U(s)) / (E(s)) = KP x (1 + 1 / (TI x s) + (TD x s) / (1 + TD / KD x s))

[0018] In the formula, KP is the proportionality coefficient, TI is the integral time, TD is the differential time, KD is the differential gain, and S is the Laplace transform complex variable.

[0019] The conditions 1-13 in step 2 described above include: Condition 1: One-time frequency modulation is removed; Condition 2: Emergency shutdown; Condition 3: One-time frequency modulation time t > 63 s; Condition 4: Rapid power reduction of the nuclear island; Condition 5: The sodium temperature in the primary circuit is greater than 320 °C or less than 300 °C, or the sodium temperature in the secondary circuit is greater than 320 °C or less than 300 °C; Condition 6: Non-steam turbine main steam pressure mode; Condition 7: The minimum superheat at the outlet of the evaporator is less than 30 °C; Condition 8: Steam turbine trip; Condition 9: The measured pressure of the main steam header is greater than 13.6 MPa or less than 12 MPa; Condition 10: The frequency difference from the power grid exceeds 0.2 Hz; Condition 11: The nuclear power of the reactor is less than 75%; Condition 12: The main feed water regulating valve is in the manual mode; Condition 13: The difference between the actual speed and the set speed of the steam turbine is less than 4 RPM and greater than -4 RPM, and it is in the non-steam turbine main steam pressure mode.

[0020] The beneficial effects of the present invention are as follows: The primary frequency modulation control technology can quickly respond to the change of the grid frequency, maintain the stability of the grid frequency by automatically adjusting the active power of the generator set, relieve the grid pressure, and improve the overall operation quality of the grid. By controlling the valve opening of the high-pressure governing valve of the steam turbine through the flow command, the output of the steam turbine can be linearly and smoothly controlled. At this time, the command of the total feed water valve remains unchanged, and the main steam header pressure is adjusted to be stable at the original value by adjusting the speed of the main feed water pump, which can effectively ensure the stability of the system pressure, avoid oscillation, and ensure the stable operation of the unit. Brief Description of the Drawings

[0021] Figure 1 It is a logic schematic diagram of a primary frequency modulation control method for a sodium-cooled fast reactor provided by the present invention;

[0022] Figure 2 It is a curve graph of the relationship between the speed difference of the steam turbine and the output power deviation. Specific Embodiments

[0023] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0024] A primary frequency modulation control method for a sodium-cooled fast reactor includes the following steps:

[0025] Step 1: The signals of the operating conditions 1 and 2 from which the signal for the unit to enter the primary frequency modulation control mode comes are in an "OR" relationship. As long as one of the conditions of the operating conditions 1 and 2 is satisfied, the primary frequency modulation control mode is put into operation.

[0026] Operating condition 1: The measured pressure of the main steam header is greater than 12.8 MPa and less than 13.2 MPa; the sodium temperature of the first loop is greater than 307 °C and less than 309 °C; and the sodium temperature of the second loop is greater than 307 °C and less than 309 °C; under the main steam pressure mode of the steam turbine and the difference between the measured speed value of the steam turbine and the set value (3000 RPM) is greater than 4 RPM; the above signals are in an "AND" relationship.

[0027] Operating condition 2: The sodium temperature of the first loop is greater than 307 °C and less than 309 °C; and the sodium temperature of the second loop is greater than 307 °C and less than 309 °C; under the main steam pressure mode of the steam turbine and the difference between the measured speed value of the steam turbine and the set value (3000 RPM) is less than -4 RPM;

[0028] The signals of the above operating conditions 1 and 2 are in an "AND" relationship.

[0029] The frequency modulation control mode includes:

[0030] Control response logic 1: The set speed value of the steam turbine of the nuclear power plant unit is 3000 RPM, and at the same time, the measured speed value of the steam turbine is received, and the difference operation is performed between the two (the set value is +, and the measured value is -);

[0031] Control response logic 2: The operation signal enters the F(x)2 (-3 ≤ F(x)2 ≤ 3) module and is converted into a power signal;

[0032] Among them, as Figure 2 shown, F(x)2 is a piecewise function which is an engineering experience formula:

[0033] 1) F(x)2 = -3, (-3000 RPM ≤ x ≤ -7.6 RPM);

[0034] 2) F(x)2 = -x / 1.2 + 10 / 3, (-7.6 RPM ≤ x ≤ -4 RPM);

[0035] 3) F(x)2 = 0, (-4 RPM ≤ x ≤ 4 RPM);

[0036] 4) F(x)2 = x / 1.2 - 10 / 3, (4 RPM ≤ x ≤ 7.6 RPM);

[0037] 5) F(x)2 = 3, (7.6 RPM ≤ x ≤ 3000 RPM);

[0038] Note: x represents the difference between the measured value and the set value of the steam turbine speed.

[0039] Control response logic 3: The power signal enters the F(x)1 (-3 ≤ F(x)2 ≤ 3) module and is converted into an energy signal. The accumulated amount is used as the flow command of the high-pressure regulating valve of the steam turbine, and the valve opening is controlled through the flow command;

[0040] Control response logic 4: The command of the main feed water valve remains unchanged;

[0041] Control response logic 5: The measured pressure and the set pressure of the main steam header enter the PID controller for calculation, and the output speed signal is used to control the speed of the main feed water pump, so as to adjust the pressure of the main steam header to be stable at the original value;

[0042] Among them, the calculation formula adopted by the PID operation module is as follows:

[0043] G(s) = (U(s)) / (E(s)) = KP x (1 + 1 / (TI x s) + (TD x s) / (1 + TD / KD x s))

[0044] In the formula, KP is the proportional coefficient, TI is the integral time, TD is the differential time, KD is the differential gain, and S is the Laplace transform complex variable.

[0045] Step 2: The signal for the unit to exit the primary frequency modulation control mode comes from the working conditions of Conditions 1 to 13. An "OR" relationship is made between the signals. As long as one of Conditions 1 - 13 is satisfied, the primary frequency modulation control mode is exited.

[0046] Condition 1: Primary frequency regulation is removed;

[0047] Condition 2: Emergency reactor shutdown;

[0048] Condition 3: Primary frequency regulation time t > 63 s;

[0049] Condition 4: Rapid reduction of nuclear island power;

[0050] Condition 5: The primary circuit sodium temperature is greater than 320 °C or less than 300 °C, or the secondary circuit sodium temperature is greater than 320 °C or less than 300 °C;

[0051] Condition 6: Non-steam turbine main steam pressure mode;

[0052] Condition 7: The minimum value of the superheat at the evaporator outlet is less than 30 °C;

[0053] Condition 8: Turbine trip;

[0054] Condition 9: The measured pressure of the main steam header is greater than 13.6 MPa or less than 12 MPa;

[0055] Condition 10: The frequency difference from the power grid exceeds 0.2 Hz;

[0056] Condition 11: The nuclear power of the reactor is less than 75%;

[0057] Condition 12: The main feed water regulating valve is in manual mode;

[0058] Condition 13: The difference between the actual speed of the steam turbine and the set speed is less than 4 RPM and greater than -4 RPM, and it is in the non-steam turbine main steam pressure mode.

[0059] Example 1: Primary frequency regulation control method for sodium-cooled fast reactor

[0060] When the speed of the steam turbine of the generating unit deviates from the set value range, a small frequency deviation will occur in the power grid frequency. At this time, the primary frequency regulation control mode is put into operation. When the primary frequency regulation control mode is put into operation, the main feed water regulating valve keeps the opening unchanged, and the main steam header pressure is adjusted to be stable at the original value by adjusting the speed of the main feed water pump. Then, according to the adjusted flow command of the high-pressure regulating valve of the steam turbine, the valve opening is controlled to adjust the load of the steam turbine generator set, so as to adjust the power grid frequency.

[0061] The set primary frequency regulation period of this unit is 63 s, and the primary frequency regulation control mode will jump out after this time period.

Claims

1. A method for controlling primary frequency modulation of a sodium-cooled fast reactor, characterized in that: The steps include: Step 1: The unit enters the primary frequency modulation control mode. The signal comes from working conditions 1 and 2. An "OR" relationship is made between the two. As long as one of the conditions of working conditions 1 and 2 is met, the unit will enter the primary frequency modulation control mode; Step 2: The unit exits the primary frequency regulation control mode. The signal comes from conditions 1 to 13. An "OR" relationship is established between the signals. As long as one of the conditions 1-13 is met, the unit exits the primary frequency regulation control mode.

2. A sodium-cooled fast reactor primary frequency modulation control method according to claim 1, characterized in that: Working condition 1 in the step 1: the measured pressure of the main steam header is greater than 12.8MPa and less than 13.2MPa; the sodium temperature of the first loop is greater than 307°C and less than 309°C; and the sodium temperature of the second loop is greater than 307°C and less than 309°C; the turbine is in the main steam pressure mode and the difference between the measured speed value of the turbine and the set value is greater than 4RPM; an "AND gate" is made between the above signals.

3. A sodium-cooled fast reactor primary frequency modulation control method as claimed in claim 2, characterized in that: The operating condition 2 in the step 1 is as follows: the sodium temperature of the first loop is greater than 307°C and less than 309°C; and the sodium temperature of the second loop is greater than 307°C and less than 309°C; the turbine is in the main steam pressure mode and the difference between the actual speed of the turbine and the set value (3000RPM) is less than -4RPM; an "AND gate" is made between the signals of the above operating conditions 1 and 2.

4. A sodium-cooled fast reactor primary frequency modulation control method as claimed in claim 1, characterized in that: The frequency modulation control mode in step 1 includes: Control response logic 1: The steam turbine speed setting value of the nuclear power plant unit is 3000RPM, and the actual speed value of the steam turbine is received at the same time, and the difference calculation is performed between the two (the setting value is +, the actual value is -).

5. A sodium-cooled fast reactor primary frequency modulation control method according to claim 1, characterized in that: The frequency modulation control mode in step 1 includes: Control response logic 2: The operation signal enters the F(x)2 (-3≤F(x)2≤3) module and is converted into a power signal.

6. A sodium-cooled fast reactor primary frequency modulation control method according to claim 1, characterized in that: The frequency modulation control mode in step 1 includes: Control response logic 3: The power signal enters the F(x)1 (-3≤F(x)2≤3) module and is converted into an energy signal. The accumulated amount is used as the flow command of the turbine high-pressure regulating valve, and the valve opening is controlled by the flow command.

7. A sodium-cooled fast reactor primary frequency modulation control method as claimed in claim 1, characterized in that: The frequency modulation control mode in step 1 includes: Control response logic 4: The water supply main valve command remains unchanged.

8. A sodium-cooled fast reactor primary frequency modulation control method as claimed in claim 1, characterized in that: The frequency modulation control mode in step 1 includes: Control response logic 5: The measured pressure of the main steam header and the set pressure enter the PID controller for calculation, and the speed signal is output to control the speed of the main feed water pump, thereby adjusting the main steam header pressure to stabilize at the original value; Among them, the calculation formula used by the PID operation module is as follows: G(s)=(U(s)) / (E(s))=KPx(1+1 / (TIxs)+(TDxs) / (1+TD / KDxs)) Where KP is the proportional coefficient, TI is the integral time, TD is the differential time, KD is the differential gain, and S is the Laplace transform complex variable.

9. A sodium-cooled fast reactor primary frequency modulation control method according to claim 1, characterized in that: Conditions 1-13 in step 2 include: condition 1: primary frequency modulation removal; condition 2: emergency shutdown; condition 3: primary frequency modulation time t>63s; condition 4: rapid power reduction of nuclear island; condition 5: primary circuit sodium temperature is greater than 320℃ or less than 300℃, or secondary circuit sodium temperature is greater than 320℃ or less than 300℃; condition 6: non-turbine main steam pressure mode; condition 7: minimum evaporator outlet superheat is less than 30℃; condition 8: turbine tripping; condition 9: main steam header measured pressure is greater than 13.6MPa or less than 12MPa; condition 10: frequency difference with power grid exceeds 0.2Hz; condition 11: reactor nuclear power is less than 75%; condition 12: main feed water regulating valve is in manual mode; condition 13: difference between actual turbine speed and set speed is less than 4RPM and greater than -4RPM, and non-turbine main steam pressure mode.

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