Power plant security power supply system

Abstract

The invention relates to a power plant security power supply system. The system comprises a generator power supply bus, a generator security power supply bus, a generator security standby power supply bus, a generator security power supply inlet wire switch, a generator security standby power supply inlet wire switch, a third power supply inlet wire switch and a security power supply switch switching control circuit. The security power supply switch switching control circuit is respectively connected with the generator security power supply incoming line switch, the generator security standby power supply incoming line switch and the third power supply incoming line switch, and is used for switching the generator security standby power supply incoming line switch to the third power supply incoming line switch when the generator fails. And controlling the generator security power supply incoming line switch, the generator security standby power supply incoming line switch and the third power supply incoming line switch to act according to a set time sequence. Safe switching of the power supply of the generator security power supply bus can be realized, so that the reliability of the generator security power supply is improved, and safe and stable operation of a unit is ensured.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power generation, and in particular to a security power supply system for a power plant. Background Art

[0002] As an important energy supply enterprise, the power plant plays a vital role in the safe and reliable power supply of its security power supply. The load carried by the power supply of the security section of the power plant refers to the load that must be kept running to ensure the safety of the unit when the generator unit is shut down due to an accident or the unit system is shut down. It mainly includes thermal control system, UPS, turbine AC lubricating oil pump, turbine turning oil pump, generator sealing oil pump and emergency lighting, etc. Once the security load is shut down, it will cause serious problems such as damage to the main equipment of the unit and failure of the automatic control system, resulting in abnormal shutdown of the unit and delaying the time for the unit to resume power supply, which will bring immeasurable negative impact and economic losses.

[0003] However, the reliability of the power supply for power plant security is still insufficient and needs to be addressed urgently. Summary of the invention

[0004] In order to solve the above problems, the present disclosure provides a power plant security power supply system. The system includes: a generator power bus, a generator security power bus, a generator security backup power bus, a generator security power incoming line switch, a generator security backup power incoming line switch, a third power incoming line switch and a security power switch switching control circuit;

[0005] The generator power bus is connected to the generator safety power bus through the generator safety power incoming switch, and the generator power bus is used to supply power to the generator safety power bus when the generator is working normally;

[0006] The generator safety power bus is connected to the generator safety standby power bus through the generator safety standby power incoming switch, and the generator safety power bus is used to supply power to the safety section load;

[0007] The generator safety standby power bus is connected to the third power supply through the third power supply incoming switch, and the generator safety standby power bus is used to supply power to the generator safety power bus through the third power supply in the event of a generator failure;

[0008] The safety power switch switching control circuit is respectively connected to the generator safety power incoming switch, the generator safety standby power incoming switch and the third power incoming switch, and is used to control the generator safety power incoming switch, the generator safety standby power incoming switch and the third power incoming switch to operate according to a set timing when the generator fails.

[0009] Optionally, the safety power switch switching control circuit includes: a generator low voltage protection device, a first time relay and a second time relay;

[0010] The first port of the generator low-voltage protection device is connected to the generator safety power supply line switch, and is used to output a trip command to the generator safety power supply line switch in the event of a generator failure;

[0011] The second port of the generator low-voltage protection device is connected to the generator safety standby power supply incoming switch through the first time relay, and is used to output a closing command to the generator safety standby power supply incoming switch through the first time relay in the event of a generator failure;

[0012] The third port of the generator low-voltage protection device is connected to the third power supply incoming switch through the second time relay, and is used to output a closing command to the third power supply incoming switch through the second time relay when the generator fails.

[0013] Optionally, the delay time of the first time relay is smaller than the delay time of the second time relay.

[0014] Optionally, the safety power switch switching control circuit further includes: a first interlocking input switch, a second interlocking input switch and a third interlocking input switch;

[0015] The first interlocking switch is connected in series between the first port of the generator low-voltage protection device and the generator safety power supply line switch, and is used to enable or disconnect the tripping instruction of the generator safety power supply line switch;

[0016] The second interlocking switch is connected in series between the second port of the generator low-voltage protection device and the first time relay, and is used to enable or disconnect the closing instruction of the generator safety standby power supply incoming switch;

[0017] The third interlocking switch is connected in series between the third port of the generator low-voltage protection device and the second time relay, and is used to enable or disconnect the closing instruction of the third power supply incoming line switch.

[0018] Optionally, the system further comprises: a diesel generator and a diesel generator power supply inlet switch;

[0019] The diesel generator is connected to the generator safety standby power bus through the diesel generator power supply incoming switch, and the diesel generator is used to supply power to the generator safety standby power bus when both the generator and the third power supply fail.

[0020] Optionally, the safety power switch switching control circuit is connected to the diesel generator, and is used to start the diesel generator after the safety backup power incoming line switch of the generator is closed.

[0021] Optionally, the switching states of the third power supply line switch and the diesel generator power supply line switch are opposite.

[0022] Optionally, the security power switch switching control circuit further includes: a third time relay;

[0023] The fourth port of the generator low-voltage protection device is connected to the diesel generator through the third time relay, and is used for outputting a start-up instruction to the diesel generator through the third time relay in the event of a generator failure.

[0024] Optionally, the safety power switch switching control circuit further includes: a fourth interlocking input switch;

[0025] The fourth interlocking switch is connected in series between the fourth port of the generator low-voltage protection device and the third time relay, and is used to enable or disconnect the start-up instruction of the diesel generator.

[0026] Optionally, in the security power switch switching control circuit, the delay time of the third time relay is equal to the delay time of the second time relay.

[0027] Optionally, the safety power switch switching control circuit further includes: a locking protection pressure plate;

[0028] The locking protection pressure plate is connected in series between the second time relay and the third power supply incoming line switch, and is used to be in a closed state when the third power supply is normal, so as to ensure that the third power supply incoming line switch can be normally closed when the generator fails;

[0029] In the event of a failure of the third power supply, it is in a non-activated disconnected state to ensure that the diesel generator power supply incoming line switch can be normally closed in the event of a failure of the generator.

[0030] Optionally, the generator low-voltage protection device is used to issue a control instruction after a first delay time in the event of a generator failure.

[0031] Optionally, the system further comprises: a generator safety section power switch;

[0032] The generator safety section power switch is connected in series between the generator power bus and the generator safety power incoming switch, and is in a closed state by default. It is used to manually control the generator power bus and the generator safety power bus to disconnect in the event of a generator failure.

[0033] In summary, the embodiments of the present disclosure provide a security power supply system for a power plant. The system comprises: a generator power bus, a generator safety power bus, a generator safety standby power bus, a generator safety power incoming switch, a generator safety standby power incoming switch, a third power incoming switch and a safety power switch switching control circuit; the generator power bus is connected to the generator safety power bus through the generator safety power incoming switch, and the generator power bus is used to supply power to the generator safety power bus when the generator is working normally; the generator safety power bus is connected to the generator safety standby power bus through the generator safety standby power incoming switch, and the generator safety power bus is used to supply power to the safety section load; the generator safety standby power bus is connected to the third power supply through the third power incoming switch, and the generator safety standby power bus is used to supply power to the generator safety power bus through the third power supply when the generator fails; the safety power switch switching control circuit is respectively connected to the generator safety power incoming switch, the generator safety standby power incoming switch and the third power incoming switch, and is used to control the generator safety power incoming switch, the generator safety standby power incoming switch and the third power incoming switch to act according to a set timing sequence when the generator fails. Since the generator safety power supply incoming switch, the generator safety standby power supply incoming switch and the third power supply incoming switch can operate according to the set timing, the power supply of the generator safety power supply bus can be safely switched, thereby improving the reliability of the generator safety power supply and ensuring the safe and stable operation of the unit.

[0034] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0036] Figure 1 The present invention is a communication diagram of a unit safety power supply system according to an exemplary embodiment.

[0037] Figure 2 The figure is a schematic diagram of a security power supply system of a power plant according to an exemplary embodiment.

[0038] Figure 3 The figure is a schematic diagram showing a switching control circuit of a security power switch according to an exemplary embodiment. DETAILED DESCRIPTION

[0039] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0040] It should be understood that the term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description.

[0041] It should be noted that the concepts of "first", "second", etc. mentioned in the present disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units. The modifications of "one" and "multiple" mentioned in the present disclosure are illustrative and not restrictive. Those skilled in the art should understand that unless otherwise clearly indicated in the context, they should be understood as "one or more". In the description of the present disclosure, unless otherwise specified, "multiple" refers to two or more than two, and other quantifiers are similar; "at least one item", "one item or multiple items" or similar expressions refer to any combination of these items, including any combination of single items or plural items.

[0042] Although operations or steps are described in a specific order in the drawings in the embodiments of the present disclosure, it should not be understood that it is required to perform these operations or steps in the specific order shown or in a serial order, or to perform all the operations or steps shown to obtain the desired results. In the embodiments of the present disclosure, these operations or steps can be performed in series; these operations or steps can also be performed in parallel; or some of these operations or steps can be performed.

[0043] The names of the messages or information exchanged between multiple devices in the embodiments of the present disclosure are only for illustrative purposes and are not used to limit the scope of these messages or information. It is understandable that before using the technical solutions disclosed in the embodiments of the present disclosure, the type, scope of use, and usage scenarios of the personal information involved in the present disclosure should be informed to the user in an appropriate manner in accordance with relevant laws and regulations and the user's authorization should be obtained.

[0044] First, the application scenario of the present disclosure is explained. The security power supply in a thermal power plant provides AC power for the security load of the generator set. It is an important power supply to ensure the safe operation of the power plant and plays a very important role. When the unit is operating normally, the 380V low-voltage plant system supplies power to the security section load. When the plant power is interrupted, the security third power supply system must be switched reliably to ensure the continuous power supply of the security load and prevent damage to important equipment, so as to ensure safe shutdown and the safety of the main equipment of the unit.

[0045] The normal power supply of the 380V accident safety power supply of the power plant is supplied by the boiler section of the unit. In the event of an accident, the safety section loses power and the third power supply or diesel generator is started through the interlocking relationship to provide reliable power supply for the safety section. The third power supply is introduced into the plant from the 10kV line of the power supply bureau, and the voltage is reduced to 380V through the safety transformer, and then sent to the safety section through the 5ZKK switch. The other power supply is sent to the safety section through the diesel engine export switch ZKK after the diesel generator is started, ensuring continuous power supply to the safety section load. The above two power supplies are completely independent of the 380V boiler section power supply, and can reliably ensure continuous power supply in the event of accident power failure in the safety section.

[0046] Figure 1 FIG. 1 is a schematic diagram showing a communication diagram of a unit safety power supply system according to an exemplary embodiment. Figure 1 As shown in the figure, taking the power failure of security section A (security PC section A of machine 1) as an example, the original implementation scheme of security section power switching is as follows:

[0047] When the security section A is tripped due to switch tripping or voltage reduction, the low voltage protection device (not shown in the figure) sends a tripping command for the working power switch 3ZKK, a closing command for the standby incoming line switch 1ZKK, a command to start the diesel generator, and a closing command for the third power switch 5ZKK.

[0048] After the above instruction is issued, the working power switch 3ZKK trips, the standby incoming line switch 1ZKK closes, and the third power switch 5ZKK closes, and the third power supply supplies power to the security section A. Since the diesel engine starts and builds pressure for about 6 seconds, the outlet switch ZKK is allowed to be closed after the pressure is built normally, so the diesel engine outlet switch ZKK is not closed at this time. At the same time, after the third power switch 5ZKK is closed normally, the third power switch 5ZKK closing position node is used to lock the diesel generator outlet switch ZKK closing. If the third power switch 5ZKK fails to be put into use (such as the 5ZKK circuit breaker fails or the third power supply is under maintenance, etc.), the diesel generator outlet switch ZKK closing and locking will not be triggered. After the diesel generator set is under normal pressure, the diesel engine outlet switch ZKK is closed to supply power to the security section A load. Among them, 11A41 is the No. 1 generator security section A power switch, which is closed by default. 5ZKK and ZKK are locking switches.

[0049] However, the above solutions have the following shortcomings:

[0050] 1. When the low voltage protection device is used to trigger the automatic switching of the backup power supply, when there is a system voltage disturbance, the low voltage abnormality is often very short-lived. Under normal circumstances, the system voltage will quickly return to normal and will not affect the operation of the system equipment. However, at this time, the low voltage protection device may misjudge and cause the power supply of the safety section to switch.

[0051] 2. When the power supply of the security section is lost in an accident, the low voltage protection device is activated, and at the same time, four instructions are triggered: tripping the working incoming line switch 3ZKK, closing the standby incoming line switch 1ZKK, closing the third power switch 5ZKK, and starting the diesel engine. At this time, due to different switch manufacturers or inconsistencies in switch characteristics, there is a deviation in the time before and after the opening and closing coordination of multiple switches, which can easily cause confusion in the order of switch tripping / closing actions and cause accidents. The correct order of switch actions should be to first trip the working power switch 3ZKK, then close the standby power switch 1ZKK, and finally close the third power switch 5ZKK and start the diesel generator.

[0052] 3. Due to the failure of the switch itself, the working power switch 3ZKK may not be opened during the switching process, or the standby power switch 1ZKK, the third power switch 5ZKK or the diesel engine export switch ZKK may not be closed. If the working power switch 3ZKK fails to open, it may cause the third power supply or the diesel generator power supply to reversely supply power to the upper bus and transformer through the unopened working power incoming switch 3ZKK. At the same time, due to the limited capacity of the third power supply and the diesel generator, the increase in the reverse power supply load may cause the third power switch or the diesel engine export switch to be overloaded, causing the switch to trip incorrectly and causing the safety section to lose power completely. Furthermore, if the switch itself fails to close, it is more likely to cause the power supply of the safety section to be lost and unable to be restored.

[0053] 4. The third power supply and diesel generator closing circuit only uses the third power switch auxiliary contact to lock the diesel generator outlet switch ZKK. When there is no electricity on the third power side or the third power switch is in the test position, the third power switch may be closed, locking the diesel generator outlet closing, and the diesel generator cannot supply power to the safety section, resulting in a complete power outage of the safety section. If the third power switch is closed successfully, the locking diesel engine release plate is mistakenly put into operation, or the locking circuit fails, it may cause the third power supply and the diesel generator to be asynchronously connected in parallel, resulting in asynchronous closing.

[0054] 5. For some safety section loads, due to the time difference in the switching process, after the working power is tripped, the residual voltage drops quickly, which may cause some important AC power circuit control power failure and cause the release or contactor to operate. At this time, even if the safety section power is successfully switched, the voltage will return to normal and some loads on site will lose power.

[0055] In view of this, a highly reliable power supply system for power plants is urgently needed. The present disclosure is described below in conjunction with specific embodiments.

[0056] Figure 2 FIG. 1 is a schematic diagram of a power plant security power supply system according to an exemplary embodiment. Figure 2 As shown, an embodiment of the present disclosure provides a power plant security power supply system, which includes: a generator power bus M1, a generator security power bus M2, a generator security backup power bus M3, a generator security power incoming line switch ZK1, a generator security backup power incoming line switch ZK2, a third power incoming line switch ZK3 and a security power switch switching control circuit.

[0057] The generator power bus M1 is connected to the generator safety power bus M2 through the generator safety power incoming switch ZK1. The generator power bus M1 is used to supply power to the generator safety power bus M2 when the generator is working normally.

[0058] The generator safety power bus M2 is connected to the generator safety standby power bus M3 through the generator safety standby power incoming switch ZK2. The generator safety power bus M2 is used to supply power to the safety section load.

[0059] The generator safety standby power bus M3 is connected to the third power supply through the third power supply incoming switch ZK3. The generator safety standby power bus M3 is used to supply power to the generator safety power bus M2 through the third power supply in case of generator failure.

[0060] The safety power switch switching control circuit is respectively connected to the generator safety power incoming line switch ZK1, the generator safety standby power incoming line switch ZK2 and the third power incoming line switch ZK3, and is used to control the generator safety power incoming line switch ZK1, the generator safety standby power incoming line switch ZK2 and the third power incoming line switch ZK3 to operate according to the set timing in the event of a generator failure.

[0061] In summary, the embodiment of the present disclosure provides a power plant security power supply system. The system includes: a generator power bus, a generator security power bus, a generator security standby power bus, a generator security power incoming switch, a generator security standby power incoming switch, a third power incoming switch and a security power switch switching control circuit. The generator power bus is connected to the generator security power bus through the generator security power incoming switch, and the generator power bus is used to supply power to the generator security power bus when the generator is working normally. The generator security power bus is connected to the generator security standby power bus through the generator security standby power incoming switch, and the generator security power bus is used to supply power to the security section load. The generator security standby power bus is connected to the third power supply through the third power incoming switch, and the generator security standby power bus is used to supply power to the generator security power bus through the third power supply when the generator fails. The safety power switch switching control circuit is respectively connected to the generator safety power incoming line switch, the generator safety standby power incoming line switch and the third power incoming line switch, and is used to control the generator safety power incoming line switch, the generator safety standby power incoming line switch and the third power incoming line switch to operate according to a set timing sequence in the event of a generator failure. Since the generator safety power incoming line switch, the generator safety standby power incoming line switch and the third power incoming line switch can operate according to a set timing sequence, the power supply of the generator safety power busbar can be safely switched, thereby improving the reliability of the generator safety power supply, thereby ensuring the safe and stable operation of the unit.

[0062] Figure 3 FIG. 1 is a schematic diagram showing a switching control circuit of a security power switch according to an exemplary embodiment. Figure 3 As shown, the safety power switch switching control circuit includes: a generator low voltage protection device, a first time relay T1 and a second time relay T2.

[0063] The first port 1 of the generator low-voltage protection device is connected to the generator safety power supply line switch ZK1, and is used to output a tripping instruction Z1 to the generator safety power supply line switch ZK1 in case of a generator failure.

[0064] The second port 2 of the generator low voltage protection device is connected to the generator safety standby power supply incoming switch ZK2 through the first time relay T1, and is used to output a closing command Z2 to the generator safety standby power supply incoming switch ZK2 through the first time relay T1 in case of generator failure.

[0065] The third port 3 of the generator low voltage protection device is connected to the third power supply line switch ZK3 through the second time relay T2, and is used to output a closing command Z3 to the third power supply line switch ZK3 through the second time relay T2 in case of a generator failure.

[0066] In some embodiments, the delay time of the first time relay T1 is less than the delay time of the second time relay T2. For example, the delay time of the first time relay T1 can be 0.5 seconds, and the delay time of the second time relay T2 can be 0.7 seconds. In this way, the generator security standby power supply line switch ZK2 can be activated before the third power supply line switch ZK3. This ensures that the switch action sequence is correct and the security power supply is switched normally.

[0067] In some embodiments, the security power switch switching control circuit further includes: a first interlocking switch LK1, a second interlocking switch LK2 and a third interlocking switch LK3.

[0068] The first interlocking switch LK1 is connected in series between the first port 1 of the generator low voltage protection device and the generator safety power supply line switch ZK1, and is used to enable or disconnect the tripping instruction Z1 of the generator safety power supply line switch ZK1.

[0069] The second interlocking switch LK2 is connected in series between the second port 2 of the generator low-voltage protection device and the first time relay T1, and is used to enable or disconnect the closing instruction Z2 of the generator safety standby power supply incoming switch ZK2.

[0070] The third interlocking switch LK3 is connected in series between the third port 3 of the generator low-voltage protection device and the second time relay T2, and is used to enable or disconnect the closing instruction Z3 of the third power supply incoming switch ZK3.

[0071] In this way, by turning on and off the first interlocking switch LK1 , the second interlocking switch LK2 and the third interlocking switch LK3 , the corresponding switch control instructions can be enabled or disconnected, which is convenient for overhauling and maintaining the equipment.

[0072] Reference Figure 2 In some embodiments, the system further includes: a diesel generator and a diesel generator power supply line switch ZK4.

[0073] The diesel generator is connected to the generator safety standby power bus M3 through the diesel generator power incoming switch ZK4. The diesel generator is used to supply power to the generator safety standby power bus M3 when both the generator and the third power supply fail.

[0074] In some embodiments, the safety power switch switching control circuit is connected to the diesel generator and is used to start the diesel generator after the generator safety backup power incoming line switch ZK2 is closed.

[0075] In some embodiments, the switch states of the third power supply line switch ZK3 and the diesel generator power supply line switch ZK4 are opposite. Exemplarily, the third power supply line switch ZK3 and the diesel generator power supply line switch ZK4 can be connected in series with a normally closed double node to block the diesel generator closing circuit, which can prevent the asynchronous closing of the third power supply and the diesel generator power supply due to a single node failure, thereby increasing system reliability.

[0076] Reference Figure 3 In some embodiments, the security power switch switching control circuit further includes: a third time relay T3.

[0077] The fourth port 4 of the generator low-voltage protection device is connected to the diesel generator through the third time relay T3, and is used to output a start instruction Z4 to the diesel generator through the third time relay T3 in case of a generator failure.

[0078] In some embodiments, the safety power switch switching control circuit further includes: a fourth interlocking input switch LK4.

[0079] The fourth interlocking switch LK4 is connected in series between the fourth port 4 of the low-voltage protection device of the generator and the third time relay T3, and is used to enable or disconnect the start instruction Z4 of the diesel generator. In this way, by turning on and off the fourth interlocking switch LK4, the start instruction Z4 of the diesel generator can be enabled or disconnected, which is convenient for the inspection and maintenance of the equipment.

[0080] In some embodiments, the safety power switch switches the control circuit, and the delay time of the third time relay T3 can be equal to the delay time of the second time relay T2, for example, both are 0.7 seconds. In this way, the response time of the diesel generator can be shortened and the reliability of the diesel generator power supply can be improved.

[0081] In some embodiments, the safety power switch switching control circuit further includes: a locking protection pressure plate LP.

[0082] The locking protection pressure plate LP is connected in series between the second time relay T2 and the third power supply line switch ZK3, and is used to be in the closed state when the third power supply is normal, so as to ensure that the third power supply line switch ZK3 can be normally closed in the case of a generator failure. In the case of a third power supply failure, it is in the non-open state to ensure that the diesel generator power supply line switch ZK4 can be normally closed in the case of a generator failure. In this way, the reliability of the system can be further improved.

[0083] In some embodiments, the generator low voltage protection device is used to issue a control instruction after a first delay time in the event of a generator failure. Exemplarily, the first delay time may be 1 second. In this way, short-term disturbances in the generator system voltage can be ignored, avoiding erroneous switching of the safety section power supply.

[0084] In some embodiments, the system further includes: a generator safety section power switch ZK5.

[0085] The generator safety section power switch ZK5 is connected in series between the generator power bus M1 and the generator safety power incoming switch ZK1. It is closed by default and is used to manually control the disconnection of the generator power bus M1 and the generator safety power bus M2 in the event of a generator failure. This can further improve the system reliability and safety.

[0086] In some embodiments, a third power supply monitoring circuit can be added to the DCS system in the centralized control room to ensure that the third power supply can be discovered and restored in time when it is out of power, ensuring normal power supply on the third power supply side. The third power supply is not shut down when the unit is operating normally; when the third power supply is shut down in an abnormal situation or when the line is under maintenance, the third power supply line switch ZK3 is in the maintenance position node and is normally closed, and the diesel generator power supply line switch ZK4 is not locked to close. In this way, it can be ensured that when the generator fails and the third power supply is unavailable, the diesel generator power supply can be normally switched to the generator security power supply bus M2 to ensure that the security section load is not disconnected.

[0087] In some embodiments, the safety section load can also be checked, and a DC control power supply circuit can be used to control the load that uses an AC control power supply and may cause the control circuit releaser and contactor to lose power; or this type of load can be transformed into a load that is maintained by the releaser and contactor after the AC power is lost, to ensure that the load equipment quickly resumes operation after the safety section power is restored.

[0088] In summary, the embodiments of the present disclosure provide a security power supply system for a power plant. The system comprises: a generator power bus, a generator safety power bus, a generator safety standby power bus, a generator safety power incoming switch, a generator safety standby power incoming switch, a third power incoming switch and a safety power switch switching control circuit; the generator power bus is connected to the generator safety power bus through the generator safety power incoming switch, and the generator power bus is used to supply power to the generator safety power bus when the generator is working normally; the generator safety power bus is connected to the generator safety standby power bus through the generator safety standby power incoming switch, and the generator safety power bus is used to supply power to the safety section load; the generator safety standby power bus is connected to the third power supply through the third power incoming switch, and the generator safety standby power bus is used to supply power to the generator safety power bus through the third power supply when the generator fails; the safety power switch switching control circuit is respectively connected to the generator safety power incoming switch, the generator safety standby power incoming switch and the third power incoming switch, and is used to control the generator safety power incoming switch, the generator safety standby power incoming switch and the third power incoming switch to act according to a set timing sequence when the generator fails. Since the generator safety power supply incoming switch, the generator safety standby power supply incoming switch and the third power supply incoming switch can operate according to the set timing, the power supply of the generator safety power supply bus can be safely switched, thereby improving the reliability of the generator safety power supply and ensuring the safe and stable operation of the unit.

[0089] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0090] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0091] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A power plant security power supply system, characterized in that: The system comprises: a generator power bus, a generator safety power bus, a generator safety standby power bus, a generator safety power incoming line switch, a generator safety standby power incoming line switch, a third power incoming line switch and a safety power switch switching control circuit; The generator power bus is connected to the generator safety power bus through the generator safety power incoming switch, and the generator power bus is used to supply power to the generator safety power bus when the generator is working normally; The generator safety power bus is connected to the generator safety standby power bus through the generator safety standby power incoming switch, and the generator safety power bus is used to supply power to the safety section load; The generator safety standby power bus is connected to the third power supply through the third power supply incoming switch, and the generator safety standby power bus is used to supply power to the generator safety power bus through the third power supply in the event of a generator failure; The safety power switch switching control circuit is respectively connected to the generator safety power incoming switch, the generator safety standby power incoming switch and the third power incoming switch, and is used to control the generator safety power incoming switch, the generator safety standby power incoming switch and the third power incoming switch to operate according to a set timing when the generator fails.

2. The system according to claim 1, characterized in that The safety power switch switching control circuit comprises: a generator low voltage protection device, a first time relay and a second time relay; The first port of the generator low-voltage protection device is connected to the generator safety power supply line switch, and is used to output a trip command to the generator safety power supply line switch in the event of a generator failure; The second port of the generator low-voltage protection device is connected to the generator safety standby power supply incoming switch through the first time relay, and is used to output a closing command to the generator safety standby power supply incoming switch through the first time relay in the event of a generator failure; The third port of the generator low-voltage protection device is connected to the third power supply incoming switch through the second time relay, and is used to output a closing command to the third power supply incoming switch through the second time relay when the generator fails.

3. The system according to claim 2, characterized in that The delay time of the first time relay is shorter than the delay time of the second time relay.

4. The system according to claim 2, characterized in that The safety power switch switching control circuit also includes: a first interlocking input switch, a second interlocking input switch and a third interlocking input switch; The first interlocking switch is connected in series between the first port of the generator low-voltage protection device and the generator safety power supply line switch, and is used to enable or disconnect the tripping instruction of the generator safety power supply line switch; The second interlocking switch is connected in series between the second port of the generator low-voltage protection device and the first time relay, and is used to enable or disconnect the closing instruction of the generator safety standby power supply incoming switch; The third interlocking switch is connected in series between the third port of the generator low-voltage protection device and the second time relay, and is used to enable or disconnect the closing instruction of the third power supply incoming line switch.

5. The system according to claim 2, characterized in that The system also includes: a diesel generator and a diesel generator power supply inlet switch; The diesel generator is connected to the generator safety standby power bus through the diesel generator power supply incoming switch, and the diesel generator is used to supply power to the generator safety standby power bus when both the generator and the third power supply fail.

6. The system according to claim 5, characterized in that The safety power switch switching control circuit is connected to the diesel generator and is used to start the diesel generator after the safety standby power incoming line switch of the generator is closed.

7. The system according to claim 5, characterized in that The switching states of the third power supply line switch and the diesel generator power supply line switch are opposite.

8. The system according to claim 5, characterized in that The security power switch switching control circuit further includes: a third time relay; The fourth port of the generator low-voltage protection device is connected to the diesel generator through the third time relay, and is used for outputting a start-up instruction to the diesel generator through the third time relay in the event of a generator failure.

9. The system according to claim 8, characterized in that The safety power switch switching control circuit further includes: a fourth interlocking input switch; The fourth interlocking switch is connected in series between the fourth port of the generator low-voltage protection device and the third time relay, and is used to enable or disconnect the start-up instruction of the diesel generator.

10. The system according to claim 8, characterized in that The security power switch switches the control circuit, and the delay time of the third time relay is equal to the delay time of the second time relay.

11. The system according to claim 5, characterized in that The safety power switch switching control circuit further includes: a locking protection pressure plate; The locking protection pressure plate is connected in series between the second time relay and the third power supply incoming line switch, and is used to be in a closed state when the third power supply is normal, so as to ensure that the third power supply incoming line switch can be normally closed when the generator fails; In the event of a failure of the third power supply, it is in a non-activated disconnected state to ensure that the diesel generator power supply incoming line switch can be normally closed in the event of a failure of the generator.

12. The system according to any one of claims 2 to 11, characterized in that: The generator low-voltage protection device is used to issue a control instruction after a first delay time in the event of a generator failure.

13. The system according to any one of claims 1 to 11, characterized in that: The system also includes: a generator safety section power switch; The generator safety section power switch is connected in series between the generator power bus and the generator safety power incoming switch, and is in a closed state by default. It is used to manually control the generator power bus and the generator safety power bus to disconnect in the event of a generator failure.

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