Power supply system and control method of VVER main pump electromagnet

Abstract

The invention belongs to the technical field of nuclear power station electrical maintenance, and particularly relates to a power supply system and a control method of a VVER main pump electromagnet, the power supply system comprises a power supply side power supply switch, a rectifier side power supply switch, a rectifier, a rectifier output switch, a direct current bus and an electromagnet power supply switch; the power side power supply switch, the rectifier side power supply switch, the rectifier, the rectifier output switch, the direct current bus and the electromagnet power switch are sequentially connected and sequentially connected with the two ends of a loop, the other end of the power side power supply switch is connected into the alternating current bus, and the other end of the electromagnet power switch is connected with the electromagnet. The electromagnet power switch comprises a primary loop and a secondary loop; and the secondary loop controls the connection and disconnection of the primary loop according to a pulse signal sent by the DCS. Daily abrasion of the bearing bush can be effectively reduced, the service life of the bearing bush is prolonged, and meanwhile frequent unit minor repair events caused by bearing bush abrasion and heat release rate rising are effectively avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power plant electrical maintenance, and in particular relates to a power supply system and a control method for a VVER main pump electromagnet. Background Art

[0002] Each of the 1-4 units of a nuclear power plant is designed with 4 reactor main coolant pumps (hereinafter referred to as main pumps) in the primary circuit. The main pump bearings are water-lubricated, and each main pump is designed with an electromagnet. The function of the electromagnet is to reduce the axial force of the thrust bearing of the main pump and reduce the wear of the bearing.

[0003] Units 1 and 2 were designed at an earlier time. The long-term operation of the electromagnets was not taken into consideration during the design. No cooling water circuit was designed for the electromagnets, and there was no cooling water supply nearby. The electromagnets were cooled by natural cooling.

[0004] In order to reduce the axial force of the thrust bearing during the normal operation of the main pump and reduce the daily wear of the bearing bushing, the electromagnets of Units 3 and 4 are designed to operate with power during the normal operation of the main pump. The structure of the electromagnets has been improved on the basis of Units 1 and 2, and a cooling water loop has been added. The cooling water pipeline is pressed inside the electromagnet along the electromagnet coil. Therefore, the cooling methods of the electromagnets of Units 3 and 4 include circulating water cooling and natural cooling.

[0005] The control logic of the electromagnets of units 1 and 2 is as follows:

[0006] 1) If the primary circuit pressure is less than 7MPa and the main pump is started, the electromagnet will not be put into operation.

[0007] 2) If the primary circuit pressure is between 7 and 13 MPa, the main pump is started, the electromagnet is automatically put into operation, and automatically stops after running for 9 seconds.

[0008] 3) If the primary circuit pressure is greater than 13MPa, the main pump is started, the electromagnet is automatically put into operation, and it automatically stops after running for 40 seconds.

[0009] 4) If the pressure in one circuit is greater than 13MPa, the main pump will be stopped, the electromagnet will automatically start operation, and will automatically stop operation after running for 4 minutes.

[0010] The rated electromagnetic force of the main pump electromagnet of units 1 and 2 is 25T during operation, and the corresponding electromagnet current is 20A. The basic operation logic is: when starting and stopping the main pump, the pressure reaches the limit, the electromagnet is put into operation, and the electromagnet stops when the operation limit is reached. The electromagnet does not operate during the normal operation of the main pump.

[0011] The control logic of the electromagnets of units 3 and 4 when they were originally designed is as follows:

[0012] 1) If the primary circuit pressure is less than 7MPa and the main pump is started, the electromagnet will not be put into operation.

[0013] 2) If the primary circuit pressure is between 7 and 13 MPa, the main pump is started and the electromagnet is put into operation. After 9 seconds, when the primary circuit pressure is less than 13 MPa, the electromagnet automatically stops operating.

[0014] 3) When the main pump is running but the electromagnet is not running, when the pressure of the first circuit is greater than 13MPa, the electromagnet will automatically start operation.

[0015] 4) When the pressure of a circuit is greater than 13MPa, the electromagnet will stop working 4 minutes after the main pump stops working.

[0016] 5) When the main pump and the electromagnet are running at the same time, when the pressure of one circuit drops below 13MPa, the electromagnet will automatically stop working.

[0017] 6) When the pressure of a circuit is greater than 13MPa and the main pump is started, the electromagnet is automatically put into operation.

[0018] The rated electromagnetic force of the main pump electromagnet of units 3 and 4 is 25T when in operation, and the corresponding electromagnet current is 20A. The basic operation logic is: when the main pump is started and stopped, the pressure reaches the limit and the electromagnet is put into operation. When the primary circuit pressure is greater than 13MPa during the operation of the main pump, the electromagnet will continue to operate.

[0019] The original electromagnet rectifier is phase-controlled rectifier, and the output parameters can only be adjusted manually, and external control adjustment is not possible. Figure 1 As shown, switches Q1' and Q2' are manual switches, which are in a closed state before the electromagnet is started. The DCS command to start the electromagnet is sent to the power supply switch Q0' on the power supply side. Q0' is closed, and the rectifier BTT10' starts with the electromagnet AS, that is, the rectifier starts with load. The load starting mode has a greater impact on the electronic components of the rectifier, which may cause a startup failure and the electromagnet cannot be started.

[0020] Due to the structural characteristics of the main pump, the external structure and size of the main pump electromagnet cannot be changed. The diameter of the cooling water pipeline of the electromagnet of units 3 and 4 is limited, resulting in limited cooling capacity of the cooling water.

[0021] The electromagnets of units 3 and 4 had five short-circuit faults between the turns of the coils. Preliminary analysis showed that the heat generated by the electromagnets did not match the cooling capacity. In October 2019, the operation mode of the electromagnets of units 3 and 4 was modified with reference to units 1 and 2. The operation mode of the main pump electromagnets of units 1-4 is exactly the same, that is, the electromagnets are only put into operation when the main pumps are started and stopped, and the electromagnets are not put into operation during the normal operation of the main pumps.

[0022] Units 1-4 have had 10 minor repairs due to the increase in heat release rate of the main pumps. Each minor repair takes at least 4 days. Excluding the cost of bearings and labor, the direct economic loss of each unit is at least 10 million yuan per day, and the direct economic loss of each minor repair is more than 40 million yuan. Each dismantling inspection found that the main pump bearings were severely worn.

[0023] For the thrust bearing of the main pump, the force applied by the primary circuit pressure is an upward axial force, and the electromagnet applies a downward reverse axial force. From the perspective of force, the operation of the electromagnet will reduce the force on the thrust bearing of the main pump.

[0024] The test proves that the heat generation of the electromagnet is reduced when the current is reduced to a certain level, the heat generation and cooling capacity of the electromagnet can reach a thermal balance, the electromagnet can maintain long-term operation, and the use of the electromagnet at a low current can reduce the heat release rate of the main pump. The long-term operation current of the electromagnet becomes smaller, and the electromagnetic force generated by the electromagnet becomes smaller. When the main pump is started and stopped, the primary axial force on the bearing is large, and the wear of the bearing increases during this period. In particular, when the primary pressure is greater than 13MPa and the main pump is shut down, the idling time of the main pump will be reduced, which may affect the timely extraction of the residual heat of the primary circuit under accident conditions, increasing the risk of safe operation of the nuclear reactor.

[0025] Therefore, it is urgent to develop a power supply system and control method for the VVER main pump electromagnet, which can reduce the axial force of the main pump thrust bearing, reduce bearing wear, maximize the safety of the main pump and unit operation, and improve the reliability of the electromagnet power supply. Summary of the invention

[0026] The object of the present invention is to provide a power supply system and control method for a VVER main pump electromagnet, which can enable the electromagnet to maintain long-term operation during the normal operation of the main pump, reduce the axial force borne by the radial thrust bearing during the normal operation of the main pump, reduce the daily wear of the bearing, and increase the service life of the bearing. At the same time, it can effectively avoid the frequent occurrence of minor repairs of the unit due to bearing wear and increased heat release rate.

[0027] The technical solution to achieve the purpose of the present invention is:

[0028] A power supply system for a VVER main pump electromagnet, the system comprising: a power supply switch on a power supply side, a power supply switch on a rectifier side, a rectifier, a rectifier output switch, a DC bus, and an electromagnet power switch; the power supply switch on the power supply side, the power supply switch on the rectifier side, the rectifier, the rectifier output switch, the DC bus, and the electromagnet power switch are connected in sequence, and the two ends of the loop are connected in sequence, the other end of the power supply switch on the power supply side is connected to the AC bus, and the other end of the electromagnet power switch is connected to the electromagnet.

[0029] The rectifier is a high-frequency switching rectifier with two identical rectifier modules connected in parallel. The rated current of each rectifier module is greater than or equal to the rated current of the electromagnet. If any module fails, the other module can still ensure the normal operation of the rectifier and the load power supply. The rectifier module can be replaced by hot swapping, and the load power supply is not affected. The operating modes of the rectifier are divided into mode A and mode B. According to the boost pulse command signal of the DCS and the parameter setting of the rectifier BTT10 mode B, mode A and mode B can be switched automatically. Among them, the output voltage of mode A is low and the current is small, and the output voltage of mode B is high and the current is large.

[0030] The electromagnet power switch comprises a primary circuit and a secondary circuit.

[0031] The primary circuit of the electromagnet power switch includes: a power switch and main contacts of a contactor; the power switch and main contacts of the contactor are connected in sequence, and the two ends of the circuit are connected in sequence, the other end of the power switch is connected to the DC bus, and the other end of the main contact of the contactor is connected to the electromagnet.

[0032] The secondary circuit of the electromagnet power switch includes: a control power switch, a start command relay, a stop command relay, a contactor coil, and a contactor auxiliary normally open contact; the control power switch, the normally open contact of the start command relay, the normally closed contact of the stop command relay, and the contactor coil are connected in sequence, and the two ends of the connected circuit are respectively connected to the live wire and the neutral wire of the control power supply, and the normally open contact of the contactor is connected in parallel to the two ends of the normally open contact of the start command relay.

[0033] The secondary circuit of the electromagnet power switch receives the pulse signal sent by the DCS, and controls the connection or disconnection of the primary circuit of the electromagnet power switch according to the pulse signal sent by the DCS.

[0034] The start command relay receives the closing pulse signal sent by the DCS, the start command relay is energized and attracted, the normally open contact is closed, the contactor is energized and attracted, the main contact of the contactor is closed, the auxiliary normally open contact of the contactor is closed, the electromagnet is powered through the main contact of the contactor, and the electromagnet is energized and operates. After the closing pulse signal disappears, the start command relay loses power, the normally open contact of the start command relay opens, and the auxiliary normally open contact of the contactor connected in parallel with the normally open contact of the start command relay keeps the electromagnet in an energized operating state.

[0035] The stop command relay receives the trip pulse signal sent by the DCS, the stop command relay is energized and energized, the normally closed contact is opened, the contactor is de-energized, the main contacts of the contactor are disconnected, and the electromagnet is de-energized and stopped.

[0036] The secondary circuit of the electromagnet power switch also includes: a boost command relay, the normally open contact of the boost command relay is connected to the rectifier control board; the boost command relay receives the boost pulse signal sent by the DCS, the boost command relay is energized, and the normally open contact closure signal is output. After receiving the contact closure signal of the boost command relay, the rectifier control board switches to mode B operation, and the rectifier outputs parameters set in mode B.

[0037] The voltage setting range of mode A is 40-220V, and the current setting range is 4-18A.

[0038] The voltage setting range of mode B is 220-325V, the current setting range is 18-22A, and the time setting range is 240S-480S.

[0039] A control method for a VVER main pump electromagnet, the method comprising an electrical control method and an instrumentation control logic control method. The electrical control method comprises:

[0040] Step 1: Before the electromagnet is put into operation, the power supply switch on the power supply side and the power supply switch on the rectifier side are manually closed;

[0041] Step 2: Start the rectifier manually or automatically, and the rectifier operates in mode A;

[0042] Step 3: Manually close the rectifier output switch and run the DC bus with power;

[0043] Step 4: Manually close the control power switch of the electromagnet power switch, push the electromagnet power switch to the working position, and manually close the main switch of the electromagnet power switch;

[0044] Step 5: When the electromagnet needs to be put into operation, the DCS sends a pulse signal for closing the electromagnet power switch, the start command relay is energized and attracted, and the normally open contact is closed;

[0045] Step 6: The contactor coil is energized, the main contacts are closed, and the electromagnet is energized and running; at the same time, the auxiliary normally open contacts of the contactor are closed, so that the contactor is kept in the energized state;

[0046] Step 7: When the electromagnet needs to be stopped, the DCS sends a pulse signal to trip the electromagnet power switch, the stop command relay is energized, and the normally closed contact opens;

[0047] Step 8: The contactor coil is de-energized, the main contacts and auxiliary normally open contacts are disconnected at the same time, and the electromagnet is de-energized and stops operating.

[0048] Step 9: When the rectifier output voltage needs to be increased, the boost command relay receives the boost pulse signal sent by the DCS, the boost command relay is energized and energized, and the normally open contact is closed;

[0049] Step 10: After the rectifier control board receives the normally open contact closure signal of the boost command relay, the rectifier switches from mode A to mode B. The rectifier outputs with the parameters set in mode B. After the rectifier runs in mode B for the rectifier set time, it automatically switches to mode A.

[0050] The instrumentation control logic control method comprises:

[0051] Step 1: If the primary circuit pressure is >7MPa and less than 13MPa, the main pump is started, and the DCS sends a pulse signal to close the electromagnet power switch. The electromagnet power switch is closed. At the same time, the DCS sends a boost pulse signal, the boost command relay is energized and energized, and the normally open contact is closed. After the rectifier receives the closing signal of the normally open contact of the boost command relay, it switches to mode B operation. The rectifier outputs the parameters set in mode B, and the electromagnet runs at the rated current. After the rectifier runs in mode B for the time set by the DCS logic, the primary circuit pressure is less than 13MPa, and the DCS sends a pulse signal to trip the electromagnet power switch. The electromagnet power switch trips and the electromagnet stops operating;

[0052] Step 2: If the main pump is running, the electromagnet is not running, the primary circuit pressure rises, and the primary circuit pressure is greater than 13MPa, the DCS sends a pulse signal to close the electromagnet power switch, the rectifier outputs the parameters set in mode A, and the electromagnet runs at a small current;

[0053] Step 3: If the pressure of the primary circuit is greater than 13MPa, the main pump is started, and the DCS sends a pulse signal to close the electromagnet power switch. The electromagnet power switch is closed. At the same time, the DCS sends a boost pulse signal, the boost command relay is energized and attracted, and the normally open contact is closed. After the rectifier receives the closing signal of the normally open contact of the boost command relay, it switches to mode B operation. The rectifier outputs the parameters set in mode B, and the electromagnet current runs at the rated current. After the rectifier runs in mode B for the rectifier set time, it automatically switches to mode A operation, and the electromagnet runs at a low current;

[0054] Step 4: If the primary circuit pressure is greater than 13MPa, the main pump and the electromagnet are running at the same time, the primary circuit pressure drops, and the primary circuit pressure is less than 13MPa. The DCS sends a pulse signal for the electromagnet power switch to trip, the electromagnet power switch is disconnected, and the electromagnet stops operating;

[0055] Step 5: If the primary circuit pressure is greater than 13MPa, the main pump is stopped, the DCS sends a boost pulse signal, the boost command relay is energized, and the rectifier receives the closing signal of the normally open contact of the boost command relay and switches to mode B. The rectifier outputs the parameters set in mode B, and the electromagnet current runs at the rated current. When the DCS logic setting time is reached, the DCS sends a trip pulse signal for the electromagnet power switch, and the electromagnet power switch is disconnected.

[0056] The beneficial technical effects of the present invention are:

[0057] 1. By adopting a power supply system and control method of a VVER main pump electromagnet provided by the present invention, when the main pump is started with a primary circuit pressure > 7MPa, the axial force borne by the radial thrust bearing during the start-up of the main pump can be reduced, thereby reducing the wear of the bearing shell.

[0058] 2. By adopting a power supply system and control method for a VVER main pump electromagnet provided by the present invention, when the main pump is stopped due to a pressure in the first circuit >13MPa, the axial force borne by the radial thrust bearing during the shutdown of the main pump can be reduced, the wear of the bearing shell can be reduced, and the idling time of the main pump can be ensured to meet the design requirements. It is ensured that the residual heat of the first circuit can be discharged in time under accident conditions, thereby ensuring the safe shutdown of the nuclear reactor.

[0059] 3. The power supply system and control method of the VVER main pump electromagnet provided by the present invention can enable the electromagnet to maintain long-term operation during the normal operation of the main pump, reduce the axial force borne by the radial thrust bearing during the normal operation of the main pump, reduce the daily wear of the bearing, and increase the service life of the bearing.

[0060] 4. The power supply system and control method of the VVER main pump electromagnet provided by the present invention can effectively avoid the frequent occurrence of minor repairs of the unit due to bearing wear and increased heat release rate.

[0061] 5. The rectifier in the power supply system of the VVER main pump electromagnet provided by the present invention is operated before the electromagnet is put into operation, which can reduce the impact on the rectifier when starting the electromagnet. At the same time, the rectifier adopts a redundant design of dual rectifier modules, which improves the reliability of the power supply of the main pump electromagnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a power supply principle diagram of an electromagnet in the prior art;

[0063] Figure 2 A power supply schematic diagram of a VVER main pump electromagnet provided by the present invention;

[0064] Figure 3 This is a power control timing diagram in a VVER main pump electromagnet control method provided by the present invention.

[0065] In the figure: Q0'-power supply switch on the power supply side; Q1'-power supply switch on the rectifier side; Q2'-rectifier output switch; BTT10'-rectifier;

[0066] Q0-power supply switch on the power supply side; Q1-rectifier side power supply switch; Q2-rectifier output switch; Q3-electromagnet power switch; Q31-main switch of the electromagnet power switch; Q4-control power switch of the electromagnet power switch; BTT10-rectifier; BUX-DC bus; KM1-contactor; K11-start command relay; K12-stop command relay; K13-boost command relay; AS-electromagnet; L1-live wire; N-neutral wire;

[0067] T1-Rectifier start-up time; T2-Condition 1 condition is met; (T3-T2)-DCS logic setting time; (T4-T2)-Rectifier mode B setting time; T5-Condition 2 condition is met; T6-Condition 3 condition is met; (T7-T6)-Rectifier mode B setting time; T8-Condition 4 condition is met; T9-Condition 5 condition is met; (T10-T9)-DCS logic setting time; (T11-T9) Rectifier mode B setting time;

[0068] Working condition 1: The primary circuit pressure is greater than 7MPa and less than 13MPa, and the main pump is started;

[0069] Working condition 2: The main pump is running, the electromagnet is not running, and the primary circuit pressure rises and is greater than 13MPa;

[0070] Working condition 3: The primary circuit pressure is greater than 13MPa and the main pump is started;

[0071] Working condition 4: The primary circuit pressure is greater than 13MPa, the main pump and the electromagnet are running at the same time, and the primary circuit pressure drops to less than 13MPa;

[0072] Working condition 5: When the primary circuit pressure is greater than 13MPa, the main pump is shut down. DETAILED DESCRIPTION

[0073] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0074] like Figure 2 As shown, a power supply system for a VVER main pump electromagnet provided by the present invention includes: a power supply switch Q0 on the power supply side, a power supply switch Q1 on the rectifier side, a rectifier BTT10, a rectifier output switch Q2, a DC bus BUX, and an electromagnet power switch Q3. The power supply switch Q0 on the power supply side, the power supply switch Q1 on the rectifier side, the rectifier BTT10, the rectifier output switch Q2, the DC bus BUX, and the electromagnet power switch Q3 are connected in sequence, and the two ends of the loop are connected in sequence. The other end of the power supply switch Q0 on the power supply side is connected to the AC bus, and the other end of the electromagnet power switch Q3 is connected to the electromagnet AS.

[0075] The rectifier BTT10 is a high-frequency switch rectifier with two identical rectifier modules connected in parallel. The rated current of each rectifier module is 20A. If any module fails, the other module can still ensure the normal operation of the rectifier and the load power supply. The rectifier module can be replaced by hot plugging, and the load power supply is not affected. The power supply switch Q0 on the power supply side, the power supply switch Q1 on the rectifier side, and the rectifier output switch Q2 are manually operated air switches.

[0076] The operation modes of the rectifier BTT10 are divided into mode A and mode B. Mode A and mode B can be switched automatically according to the boost pulse command signal of the DCS and the parameter setting of the rectifier BTT10 mode B. Among them, the output voltage of mode A is low and the current is small, and the output voltage of mode B is high and the current is large.

[0077] like Figure 2 As shown, the electromagnetic power switch Q3 includes a primary circuit and a secondary circuit.

[0078] The primary circuit includes the power switch Q31 of the electromagnet power switch Q3 and the main contact of the contactor KM1; the power switch Q31 of the electromagnet power switch Q3 and the main contact of the contactor KM1 are connected in series, and the two ends of the circuit are connected in series. The other end of the power switch of the electromagnet power switch Q3 is connected to the DC bus, and the other end of the main contact of the contactor is connected to the electromagnet. The power switch Q31 of the electromagnet power switch Q3 is a manually operated air switch.

[0079] The secondary circuit includes the control power switch Q4, the start command relay K11, the auxiliary normally open contact and coil of the contactor KM1, and the stop command relay K12; the control power switch Q4, the normally open contact of the start command relay K11, the normally closed contact of the stop command relay K12, and one end of the coil of the contactor KM1 are connected in sequence, the other end of the coil of the contactor KM1 is connected to the neutral line N, the other end of the control power switch Q4 is connected to the live line L1 of the control power supply, and the auxiliary normally open contact of the contactor KM1 is connected in parallel to the two ends of the normally open contact of the start command relay K11. The secondary circuit of the electromagnet power switch Q3 controls the connection and disconnection of the primary circuit by receiving the closing and tripping signals of the DCS. The control power switch Q4 is a manually operated air switch.

[0080] The secondary circuit also includes a boost command relay Q13, and the normally open contact of the boost command relay is connected to the control panel of the rectifier BTT10; the boost command relay K13 receives the boost pulse signal sent by the DCS, the boost command relay K13 is energized and energized, and outputs a normally open contact closure signal. After receiving the contact closure signal of the boost command relay K13, the rectifier BTT10 switches to mode B operation, and the rectifier outputs with the parameters set in mode B. After mode B runs for the rectifier set time, it automatically switches to mode A operation.

[0081] In a specific implementation, the voltage setting value of mode A is 180V, and the current setting value is 14A; the voltage setting value of mode B is 260V, the current setting range is 20A, and the time setting range is 240S.

[0082] The present invention provides a control method for a VVER main pump electromagnet, which includes an electrical control method and an instrumentation control logic control method.

[0083] In a specific embodiment, Figure 2 As shown, the electrical control method includes:

[0084] Step 1: Before the electromagnet AS is put into operation, the power supply switch Q0 on the power supply side and the power supply switch Q1 on the rectifier side are manually closed;

[0085] Step 2: Manually or automatically start the rectifier BTT10, and the rectifier operates in mode A;

[0086] Step 3: The rectifier output switch Q2 is manually closed, and the DC bus BUX is energized and running;

[0087] Step 4: Manually close the control power switch Q4 of the electromagnet power switch, push the electromagnet power switch Q3 to the working position, and manually close the main switch Q31 of the electromagnet power switch Q3;

[0088] Step 5: When the electromagnet AS needs to be put into operation, the DCS sends a pulse signal to close the electromagnet power switch Q3, and the start command relay K11 is energized and attracted, and the normally open contact is closed;

[0089] Step 6: The coil of contactor KM1 is energized, the main contact is closed, and the electromagnet AS is energized and running; at the same time, the auxiliary normally open contact of contactor KM1 is closed, so that contactor KM1 is kept in the energized state;

[0090] Step 7: When the electromagnet AS needs to be shut down, the DCS sends a pulse signal to trip the electromagnet power switch Q3, and the stop command relay K12 is energized and attracted, and the normally closed contact opens;

[0091] Step 8: The contactor KM1 coil is de-energized, the main contacts and auxiliary normally open contacts of the contactor are disconnected at the same time, and the electromagnet AS is de-energized and stops operating.

[0092] In a specific embodiment, Figure 2 , Figure 3 As shown, the instrumentation control logic control method includes:

[0093] Step 1: At T2, the primary circuit pressure is >7MPa and less than 13MPa, the main pump is started, and the DCS sends a pulse signal to close the electromagnet power switch Q3. The electromagnet power switch Q3 is closed. At the same time, the DCS sends a boost pulse signal, the boost command relay K13 is energized and energized, and the normally open contact is closed. After receiving the closing signal of the normally open contact of the boost command relay K13, the rectifier BTT10 switches to mode B operation. The rectifier BTT10 outputs with mode B parameters, and the electromagnet operates with a rated current of 20A. At T3, the rectifier BTT10 operates in mode B until the DCS logic setting time of 9S. The primary circuit pressure is less than 13MPa. The DCS sends a pulse signal to trip the electromagnet power switch Q3. The electromagnet power switch Q3 trips, and the electromagnet AS stops operating;

[0094] Step 2: At time T5, the main pump is running, the electromagnet AS is not running, the primary circuit pressure rises, and the primary circuit pressure is greater than 13MPa. The DCS sends a pulse signal to close the electromagnet power switch Q3, and the rectifier BTT10 outputs the parameters in mode A, and the electromagnet AS runs at a current of 14A.

[0095] Step 3: At T6, the primary circuit pressure is greater than 13MPa, the main pump is started, and the DCS sends a pulse signal to close the electromagnet power switch Q3. The power switch Q3 is closed. At the same time, the DCS sends a boost pulse signal, the boost command relay K13 is energized and attracted, and the normally open contact is closed. After receiving the closing signal of the normally open contact of the boost command relay K13, the rectifier BTT10 switches to mode B operation. The rectifier outputs with mode B parameters, and the electromagnet current runs at a rated current of 20A. At T7, the rectifier runs in mode B until the rectifier set time of 240S, and then automatically switches to mode A operation, and the electromagnet AS runs at a current of 14A;

[0096] Step 4: At time T8, the primary circuit pressure is greater than 13MPa, the main pump and the electromagnet AS are running at the same time, the primary circuit pressure drops, and the primary circuit pressure is less than 13MPa. The DCS sends a trip pulse signal of the electromagnet power switch Q3, the electromagnet power switch Q3 is disconnected, and the electromagnet AS stops operating;

[0097] Step 5: At T9, the primary circuit pressure is greater than 13MPa, the main pump is stopped, the DCS sends a boost pulse signal, the boost command relay K13 is energized, and the rectifier BTT10 receives the closing signal of the normally open contact of the boost command relay K13 and switches to mode B operation. The rectifier outputs with mode B parameters, and the electromagnet current runs at the rated current of 20A. At T10, when the DCS logic setting time reaches 240S, the DCS sends a trip pulse signal of the electromagnet power switch Q3, the electromagnet power switch Q3 is disconnected, and the electromagnet AS stops operating.

[0098] The present invention is described in detail above with reference to the accompanying drawings and embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. The contents not described in detail in the present invention can adopt the existing technology.

Claims

1. A power supply system for a VVER main pump electromagnet, characterized in that: The system comprises: a power supply switch (Q0) on the power supply side, a power supply switch (Q1) on the rectifier side, a rectifier (BTT10), a rectifier output switch (Q2), a DC bus (BUX), and an electromagnet power switch (Q3); the power supply switch (Q0) on the power supply side, the power supply switch (Q1) on the rectifier side, the rectifier (BTT10), the rectifier output switch (Q2), the DC bus (BUX), and the electromagnet power switch (Q3) are connected in sequence, and the two ends of the loop are connected in sequence, the other end of the power supply switch (Q0) on the power supply side is connected to the AC bus, and the other end of the electromagnet power switch (Q3) is connected to the electromagnet; The electromagnet power switch (Q3) includes a primary circuit and a secondary circuit; the secondary circuit controls the connection and disconnection of the primary circuit according to the pulse signal sent by the DCS.

2. A power supply system for a VVER main pump electromagnet according to claim 1, characterized in that: The primary circuit of the electromagnet power switch (Q3) comprises: a power switch (Q31) and main contacts of a contactor (KM1); the power switch (Q31) and the main contacts of the contactor (KM1) are connected in series, connecting two ends of the circuit, the other end of the power switch (Q31) is connected to a DC bus, and the other end of the main contact of the contactor (KM1) is connected to the electromagnet; the conduction and disconnection of the primary circuit can make the electromagnet energized or de-energized.

3. A power supply system for a VVER main pump electromagnet according to claim 1, characterized in that: The secondary circuit of the electromagnet power switch (Q3) comprises: a control power switch (Q4), a start command relay (K11), a stop command relay (K12), a contactor (KM1) coil, and an auxiliary normally open contact of the contactor (KM1); the control power switch (Q4), the normally open contact of the start command relay (K11), the normally closed contact of the stop command relay (K12), and the coil of the contactor (KM1) are connected in sequence, the other end of the coil of the contactor KM1 is connected to a neutral line N, the other end of the control power switch Q4 is connected to a live line L1 of the control power supply, and the normally open contact of the contactor (KM1) is connected in parallel to both ends of the normally open contact of the start command relay (K11); the start command relay (K11) and the stop command relay (K12) of the secondary circuit receive a pulse signal sent by a DCS, and control the connection or disconnection of the primary circuit of the electromagnet power switch according to the pulse signal sent by the DCS.

4. A power supply system for a VVER main pump electromagnet according to claim 1, characterized in that: The secondary circuit of the electromagnet power switch (Q3) also includes: a boost command relay (K13), the normally open contact of the boost command relay (K13) is connected to the rectifier (BTT10) control board; the boost command relay (K13) receives the boost pulse signal sent by the DCS, the boost command relay (K13) is energized, and outputs a normally open contact closure signal, and the rectifier (BTT10) control board switches to mode B operation after receiving the contact closure signal of the boost command relay (K13), and the rectifier (BTT10) outputs parameters set in mode B.

5. A power supply system for a VVER main pump electromagnet according to claim 1, characterized in that: The operation modes of the rectifier (BTT10) are divided into mode A and mode B. Mode A and mode B can be automatically switched according to the boost pulse command signal of the DCS and the parameter setting of the rectifier (BTT10) mode B.

6. A power supply system for a VVER main pump electromagnet according to claim 5, characterized in that: The voltage setting range of mode A is 40-220V, and the current setting range is 4-18A; the voltage setting range of mode B is 220-325V, the current setting range is 18-22A, and the time setting range is 240S-480S.

7. A method for controlling a VVER main pump electromagnet, characterized in that: The control method includes an electrical control method and an instrumentation and control logic control method.

8. A VVER main pump electromagnet control method according to claim 7, characterized in that: The electrical control method comprises: Step 1: Before the electromagnet (AS) is put into operation, the power supply switch (Q0) on the power supply side and the power supply switch (Q1) on the rectifier side are manually closed; Step 2: Manually or automatically start the rectifier (BTT10), and the rectifier (BTT10) operates in mode A; Step 3: The output switch (Q2) of the rectifier (BTT10) is manually closed, and the DC bus (BUX) is energized; Step 4: Manually close the control power switch (Q4) of the electromagnet power switch (Q3), push the electromagnet power switch (Q3) to the working position, and manually close the main switch (Q31) of the electromagnet power switch (Q3); Step 5: When the electromagnet (AS) needs to be put into operation, the DCS sends a closing pulse signal to the electromagnet power switch (Q3), the start command relay (K11) is energized and attracted, and the normally open contact is closed; Step 6: The contactor (KM1) coil is energized, the main contacts are closed, and the electromagnet (AS) is energized and running; at the same time, the auxiliary normally open contact of the contactor (KM1) is closed, so that the contactor (KM1) is self-maintained in the energized state; Step 7: When the electromagnet (AS) needs to be stopped, the DCS sends a trip pulse signal to the electromagnet power switch (Q3), the stop command relay (K12) is energized, and the normally closed contact opens; Step 8: The contactor (KM1) coil is de-energized, the main contacts and auxiliary contacts are disconnected at the same time, and the electromagnet (AS) is de-energized and stops operating; Step 9: When the output voltage of the rectifier (BTT10) needs to be increased, the boost command relay (K13) receives the boost pulse signal sent by the DCS, the boost command relay (K13) is energized and attracted, and the normally open contact is closed; Step 10: After the rectifier (BTT10) control board receives the normally open contact closure signal of the boost command relay (K13), the rectifier (BTT10) switches from mode A to mode B, and the rectifier (BTT10) outputs with the parameters set in mode B. After the rectifier (BTT10) runs in mode B for the set time of the rectifier (BTT10), it automatically switches to mode A.

9. A VVER main pump electromagnet control method according to claim 7, characterized in that: The instrumentation control method comprises: Step 1: If the primary circuit pressure is >7MPa and less than 13MPa, the main pump is started, and the DCS sends a pulse signal to close the electromagnet power switch (Q3). The electromagnet power switch is closed. At the same time, the DCS sends a boost pulse signal, and the boost command relay (K13) is energized and energized, and the normally open contact is closed. After the rectifier (BTT10) receives the closing signal of the normally open contact of the boost command relay (K13), it switches to mode B operation. The rectifier (BTT10) outputs the parameters set in mode B, and the electromagnet (AS) operates at the rated current; after the rectifier (BTT10) operates in mode B for the time set by the DCS logic, the primary circuit pressure is less than 13MPa, and the DCS sends a pulse signal to trip the electromagnet power switch (Q3). The electromagnet power switch (Q3) trips, and the electromagnet (AS) stops operating; Step 2: If the main pump is running, the electromagnet (AS) is not running, the primary circuit pressure rises, and the primary circuit pressure is greater than 13MPa, the DCS sends a pulse signal to close the electromagnet power switch (Q3), the rectifier (BTT10) outputs the parameters set in mode A, and the electromagnet (AS) runs at a small current; Step 3: If the pressure of one circuit is greater than 13MPa, the main pump is started, and the DCS sends a pulse signal to close the electromagnet power switch (Q3). The electromagnet power switch is closed. At the same time, the DCS sends a boost pulse signal, and the boost command relay (K13) is energized and attracted, and the normally open contact is closed. After the rectifier (BTT10) receives the closing signal of the normally open contact of the boost command relay (K13), it switches to mode B operation. The rectifier (BTT10) outputs the parameters set in mode B, and the electromagnet (AS) current runs at the rated current; after the rectifier (BTT10) runs in mode B for the set time of the rectifier (BTT10), it automatically switches to mode A operation, and the electromagnet (AS) runs at a low current; Step 4: If the primary circuit pressure is greater than 13MPa, the main pump and the electromagnet (AS) operate simultaneously, the primary circuit pressure drops, and the primary circuit pressure is less than 13MPa. The DCS sends a pulse signal to trip the electromagnet power switch (Q3), the electromagnet power switch (Q3) is disconnected, and the electromagnet (AS) stops operating; Step 5: If the pressure in one circuit is greater than 13MPa, the main pump is stopped, and the DCS sends a boost pulse signal. The boost command relay (K13) is energized, and the rectifier (BTT10) receives the closing signal of the normally open contact of the boost command relay (K13) and switches to mode B operation. The rectifier (BTT10) outputs with the parameters set in mode B, and the electromagnet (AS) current runs at the rated current; when the DCS logic setting time is reached, the DCS sends a trip pulse signal for the electromagnet power switch (Q3), and the electromagnet power switch (Q3) is disconnected.

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