Security power supply system based on black-start generator

Abstract

The utility model belongs to the technical field of security power supplies, and particularly discloses a security power supply system based on a black-start generator. Through combined logic control of the transformer and the circuit breaker, the black-start diesel generator in high-voltage operation is successfully applied to the normal-voltage security power supply, so that the expenditure of a special accident security diesel generator can be saved, and a black-start system and a security power supply system can be quickly switched when a fault occurs. The device is suitable for being popularized and used in thermal power plants and gas turbine power plants needing to be provided with black-start diesel generators.

Description

Technical Field

[0001] The utility model belongs to the technical field of security power supply, and specifically discloses a security power supply system based on a black start generator. Background Art

[0002] For thermal power plants or gas turbine power plants that operate in isolated grids or have insufficient grid support capacity, black start diesel generators will be configured to output high voltage power. For security power supply systems, a separate set of emergency security diesel generators are often set up to output normal voltage power.

[0003] Both black start diesel generators and accident safety diesel generators are equipped with dedicated control cabinets, resulting in a waste of resources, and the two systems often have their own control logic, which is difficult to be compatible. Since the probability of accidents is not high, this conventional configuration will cause a large number of resources to be idle. Designing a safety power supply system that can take into account both MCC (motor control center) power supply under general fault conditions and black start recovery when the entire power grid has a system failure is an urgent problem that power plant technicians need to solve. Utility Model Content

[0004] In order to solve the technical problems listed in the background technology, the utility model provides a security power supply system based on a black start generator. The specific technical solution is as follows:

[0005] A safety power supply system based on a black start generator comprises a high-voltage black start bus, multiple black start diesel generators and a special control cabinet, a high-voltage standby transformer, a high-voltage standby section, a high-voltage to normal-voltage transformer, a normal-voltage safety PC (high-power power center), and a normal-voltage safety MCC; the multiple black start diesel generators are electrically connected to the special control cabinet and connected in parallel to the high-voltage black start bus, the high-voltage black start bus and the high-voltage standby transformer are connected in parallel to the high-voltage standby section, the high-voltage standby section serves as a standby power supply for a high-voltage working section used in a factory, and is electrically connected to the normal-voltage safety PC through the high-voltage to normal-voltage transformer, and the normal-voltage safety PC is electrically connected to the normal-voltage safety MCC.

[0006] Preferably, the high voltage is 6000V and the normal voltage is 380V.

[0007] Preferably, the connecting wires of all primary lines are provided with circuit breakers at the current input and output ends.

[0008] Preferably, the normal-pressure security PC and the working PC cooperate through the ATS as the power source of the normal-pressure MCC.

[0009] Compared with the prior art, the utility model has the following advantages:

[0010] The utility model provides a safety power supply system based on a black start generator, which can not only save the expense of a special accident safety diesel generator, but also ensure the normal operation of the black start system and the safety power supply system, thus saving resources and enabling a quick response when a fault occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The utility model is a wiring diagram of a security power supply system based on a black start generator in an embodiment of the utility model. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on this embodiment, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0013] refer to Figure 1 This embodiment provides a security power supply system based on a black start generator, including a set of high-voltage black start diesel generator sets, which are composed of a 6kV black start bus, multiple diesel generators and a dedicated control cabinet. In addition to meeting the power supply needs of the power plant during black start, the black start diesel generator set can also be used as an emergency generator set after the power plant is put into normal operation.

[0014] It also includes a 6kV standby section to provide backup power to the 6kV plant working section of the unit. Its two power supplies come from the high-voltage diesel generator set and the starting / standby transformer respectively.

[0015] A low-voltage safety transformer is also installed, and the power supply comes from the 6kV standby section.

[0016] There are security MCCs for machines 1 to 2. The two power supplies for each security MCC section come from working PC sections 1 to 2 and the security PC section respectively. ATS is also set up to realize dual power supply switching.

[0017] The black start logic of the system is as follows:

[0018] 1) When the power plant starts black, the diesel generator sets start in sequence. When the detected voltage and frequency reach the rated value, the synchronous closing mode is adopted, and the diesel generator dedicated control cabinet issues GCB1~GCBN (GCB is the abbreviation of the generator output circuit breaker, 1, N are serial numbers) closing instructions, and each unit is connected to the 6kV black start bus. When the voltage of the black start bus section is detected to be normal, the diesel generator dedicated control cabinet will then issue 2DL (DL is the abbreviation of the circuit breaker) tripping, 0DL closing, and 1DL closing instructions in sequence, and the diesel generator set will provide power to the 6KV standby section, and then the 6kV standby section will provide power to the 6kV working section to meet the black start power supply needs of the entire plant.

[0019] 2) When the unit is successfully black-started and connected to the system, the 6kV working section of the unit is switched from the backup power supply to the 6kV working power supply.

[0020] 3) When the voltage on the low-voltage side of the starting / standby transformer is detected to be normal and the reverse switching command from the operator is received, the frequency and phase of the diesel generator are adjusted and the reverse synchronous closing method is adopted. The 2DL closing command is issued by the dedicated control cabinet for the diesel generator.

[0021] 4) The diesel generators are deloaded and shut down in sequence, disconnecting GCB1 to GCBN. Finally, the dedicated control cabinet for the diesel generators issues 0DL and 1DL tripping commands, and the black start is completed.

[0022] The system security power logic is as follows:

[0023] 1) During normal operation

[0024] When the security PC is operating normally, the security transformer is powered by the 6kV standby section, and the unit security MCC is powered by the plant working PC. At this time, 2DL, 3DL, and 4DL are in the closed state, 1DL and 0DL are in the tripped state, and the ATS switch of the security MCC is closed on the plant working PC side. (If the above switches are disconnected due to failure or maintenance, their correct position must be ensured before the diesel generator set is started)

[0025] 2) Working power switch

[0026] If the working PC side currently powered by the security MCC loses power, its incoming ATS switch detects the circuit power failure and automatically switches to the security PC side for power supply. If the working PC side power supply is detected to be normal, it automatically or manually switches to the working PC side for power supply.

[0027] 3)Safety power switch

[0028] When the diesel generator control system is in the automatic start state, if a power outage occurs in the entire plant, the diesel generator should be able to quickly start one or two groups according to the preset "starting conditions" (specifically, it can be set in advance according to the required capacity of the AC security power supply) to meet the needs of the security power supply for the entire plant. At this time, the diesel generator sets start in sequence. When the detected voltage and frequency reach the rated value, the synchronous closing method is adopted, and the GCB closing command is issued by the diesel generator special control cabinet, and each unit is connected to the 6kV black start bus. When the voltage of the black start bus section is detected to be normal, the diesel generator special control cabinet will issue 2DL tripping, 0DL, 1DL, 3DL, and 4DL closing commands in sequence. At this time, the working PC side currently powered by the security MCC loses power, and its incoming ATS switch detects that the circuit loses power and has automatically switched to the security PC side for power supply.

[0029] 4) Switch after the working power is restored

[0030] The diesel generator dedicated control cabinet detects that the voltage on the low-voltage side of the starting / standby transformer is normal. After receiving the reverse switching command from the operator, it adjusts the frequency and phase of the diesel generator and adopts the reverse synchronous closing method. The diesel generator dedicated control cabinet issues a 2DL closing command. The diesel generators are sequentially unloaded and shut down, and the GCB is disconnected. Finally, the diesel generator dedicated control cabinet issues 0DL and 1DL tripping commands, and the diesel generator set exits operation.

[0031] 5) Diesel generator starting conditions

[0032] There are two groups of starting conditions below. “Safety power switching” can select one of them as the starting condition according to the operation requirements.

[0033] Start condition 1: When the 380V security PC section loses voltage, start the diesel generator;

[0034] Start condition 2: When the 380V security MCC section loses voltage, the diesel generator is started;

[0035] The diesel generator test logic of this system is as follows:

[0036] When the no-load test is selected, the unit should be able to be started manually locally to the rated voltage and frequency, but the generator outlet switch GCB is not closed, and the switch in the test position can be tested.

[0037] When the load test is selected, the diesel generator sets are started in sequence. When the detected voltage and frequency reach the rated value, the synchronous closing method is adopted, and the diesel generator dedicated control cabinet issues GCB1~GCBN closing instructions, and each unit is connected to the 6kV black start bus. When the black start bus section voltage is detected to be normal, first check whether 1DL is in the closed state, and then adopt the synchronous closing method, and the diesel generator dedicated control cabinet issues 0DL closing instructions, and the black start diesel generator set runs with the 6KV standby section load.

[0038] After the test is completed, first reduce the load and stop, manually disconnect the GCB, and finally disconnect 0DL and 1DL, and the test is completed.

[0039] The diesel generator stop conditions of this system are as follows:

[0040] The diesel generator is manually shut down. After the black start of the power plant is completed or the whole plant is safely shut down, the reverse synchronous switching of the diesel generator is completed, the no-load test is completed, and the load test is completed, the diesel generator can be stopped by issuing a command through the DCS, or the diesel generator can be stopped locally.

[0041] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A security power supply system based on a black start generator, characterized in that: It includes a high-voltage black-start bus, multiple black-start diesel generators and a dedicated control cabinet, a high-voltage standby transformer, a high-voltage standby section, a high-voltage to normal-voltage transformer, a normal-voltage safety PC, and a normal-voltage safety MCC; multiple black-start diesel generators are electrically connected to the dedicated control cabinet and connected in parallel to the high-voltage black-start bus, and the high-voltage black-start bus and the high-voltage standby transformer are connected in parallel to the high-voltage standby section. On the one hand, the high-voltage standby section serves as a backup power supply for the factory's high-voltage working section, and on the other hand, it is electrically connected to the normal-voltage safety PC through the high-voltage to normal-voltage transformer, and the normal-voltage safety PC is electrically connected to the normal-voltage safety MCC.

2. A security power supply system based on a black start generator according to claim 1, characterized in that: The high voltage is 6000V, and the normal voltage is 380V.

3. A security power supply system based on a black start generator according to claim 2, characterized in that: All primary circuit connecting wires are equipped with circuit breakers at the current input and output ends.

4. A security power supply system based on a black start generator as claimed in claim 3, characterized in that: The normal-pressure security PC and working PC work together as the power source for the normal-pressure MCC through ATS.

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