Boiler flame detection power supply cabinet

Abstract

The utility model discloses a boiler flame detection power supply cabinet, belongs to the technical field of flame detection power supplies, and solves the problem that all flame detection power supplies are powered off due to manual misoperation, switch faults and the like of a main empty switch in a power supply loop of the conventional flame detection power supply. Comprising an A-side power supply cabinet and a B-side power supply cabinet, the A-side power supply cabinet comprises an A-side power supply loop and an A-side flame detection power circuit breaker; the input end of the power supply module A1 is connected in parallel with the input end of the intermediate relay KA1 and then is connected with the output end of the null switch QF1, and the input end of the null switch QF1 is connected with a station service power supply; the output end of the power supply module A1 is connected in parallel with the input end of the intermediate relay KA3 and then is connected with the first input end of the switching power supply; according to the utility model, the A-side power supply cabinet and the B-side power supply cabinet are arranged to distribute the flame detection electricity of each burner in a scattered manner, and the fault generated by the single-side power supply cabinet does not cause the coal mill misfire detection tripping and the whole hearth misfire detection MFT, so that the safety and reliability of the flame detection power supply are greatly improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of flame detector power supplies and relates to a boiler flame detector power supply cabinet. Background Technique

[0002] The main function of a boiler flame detector is to detect the combustion characteristics of a flame in real time. By monitoring the combustion conditions, it ensures the safe operation of the boiler. Once the flame combustion state does not meet the normal conditions or the flame goes out, it can send out an alarm message in time to ensure that the fuel supply stops when the boiler extinguishes. And the boiler flame detector power supply is an important part of the boiler flame detector system.

[0003] In the first-phase project of Panji Power Plant, as Figure 1 shown, the boiler flame detector power supply cabinet is designed such that two-way alternating current 220V voltage is respectively converted into direct current 24V voltage through power modules. The two-way power modules are coupled through diodes in a half-bridge circuit, and then the 24V direct current is output to each flame detector power supply through the air switch QF4. As Figure 2 shown, each flame detector probe power supply is independently designed, and a fuse is designed in its respective circuit. When a single probe power supply circuit fails and the fuse blows, it can prevent the total output air switch QF4 from tripping.

[0004] Actually, this design scheme has the following two problems: (1) There is a risk of misoperation of the total output air switch QF4. When the air switch QF4 is disconnected due to human misoperation or switch failure, etc., all the flame detector power supplies will lose power, the full furnace flame protection action will occur, and the unit will trip; (2) The two-way direct current power supplies are coupled through diodes in a half-bridge circuit. When a diode fails, the 24V power supply will be lost, which will also cause the flame detector power supplies to lose power, the full furnace flame protection action will occur, and the unit will trip. Moreover, the method of using diodes to couple the two-way direct current power supplies also violates the requirements of the latest twenty-five anti-measures. The problems generated above seriously affect the safe and stable operation of the unit, and it is urgent to propose an optimized transformation scheme for the boiler flame detector power supply circuit. Content of the Utility Model

[0005] The technical solution of the utility model is used to solve the problems that in the existing power supply circuit of the flame detector power supply, the total air switch is disconnected due to human misoperation and switch failure, etc., resulting in the power failure of all the flame detector power supplies, and the existing two-way direct current power supplies are easily powered off by using diode coupling, resulting in the unit tripping.

[0006] The utility model solves the above technical problems through the following technical solutions:

[0007] A boiler flame detector power supply cabinet includes an A-side power supply cabinet and a B-side power supply cabinet with the same structure; the A-side power supply cabinet includes an A-side power supply circuit and an A-side flame detector power breaker; the A-side power supply circuit includes air switches QF1-2, intermediate relays KA1-5, power modules A1-2, and a switching power supply.

[0008] The input end of power module A1 is connected in parallel with the input end of intermediate relay KA1, and then connected to the output end of air switch QF1. The input end of air switch QF1 is connected to the plant power supply; the output end of power module A1 is connected in parallel with the input end of intermediate relay KA3, and then connected to the first input end of the switching power supply.

[0009] The input end of power module A2 is connected in parallel with the input end of intermediate relay KA2, and then connected to the output end of air switch QF2. The input end of air switch QF2 is connected to the UPS power supply; the output end of power module A2 is connected in parallel with the input end of intermediate relay KA4, and then connected to the second input end of the switching power supply; the output end of the switching power supply is connected in parallel with the input end of intermediate relay KA5, and then connected to the A-side flame detector power breaker.

[0010] The A-side flame detector power breaker includes air switches QF4-9 and fuses FU1-30; the input ends of air switches QF4-6 are connected together and then connected to the output end of the switching power supply; fuses FU1-6 are connected in parallel and then connected to the output end of air switch QF4; fuses FU7-12 are connected in parallel and then connected to the output end of air switch QF5; fuses FU13-18 are connected in parallel and then connected to the output end of air switch QF6; fuses FU19-21 are connected in parallel and then connected to the output end of air switch QF7; fuses FU22-27 are connected in parallel and then connected to the output end of air switch QF8; fuses FU28-30 are connected in parallel and then connected to the output end of air switch QF9.

[0011] Further, the output end of intermediate relay KA1 sends a plant power supply fault alarm signal.

[0012] Further, the output end of intermediate relay KA2 sends a UPS power supply fault alarm signal.

[0013] Further, the output end of intermediate relay KA5 sends a switching power supply fault alarm signal.

[0014] Further, the model of the switching power supply is CP-C.1-A-RU.

[0015] Further, both the plant power supply and the UPS power supply are 220V.

[0016] Further, the models of the power supply modules A1-2 are CP-S.1 24 / 10.0.

[0017] Further, the models of the relays KA1-5 are RXM2LB2P7.

[0018] The advantages of the present utility model are as follows:

[0019] (1) By optimizing and transforming the dual-power switching device for boiler flame detectors and sending the power loss alarms of each power supply to the DCS, the present utility model shortens the time for eliminating defects in on-site power supply faults and improves the reliability of equipment operation.

[0020] (2) By adopting a 24V DC switching power supply to replace the existing half-bridge circuit for coupling two power supplies, the present utility model avoids the situation of power loss in the output power supply when a single input power supply fails or a diode is damaged.

[0021] (3) Based on the criterion of "four out of six" for the flame detector protection judgment of the coal layer burner, the present utility model arranges the power supply cabinets on the A side and B side to disperse the power supply for the flame detectors of each burner. The faults occurring in a single-sided power supply cabinet will not cause the flame detector of the coal mill to trip due to loss of power or trigger the MFT for the entire furnace due to loss of flame detectors, greatly improving the safety and reliability of the power supply for the flame detectors.

[0022] (4) By dispersing the arrangement of the flame detector probes of each burner, the present utility model avoids the risk of loss of the flame detector power supply caused by a single air switch failure in the traditional circuit, greatly improving the safety and reliability and significantly reducing the safety risk of the unit.

[0023] (5) The power supply circuit designed by the present utility model is simple in design and strong in reliability, and is applicable to the design of the control power supply circuits for various important equipment in industrial production, especially for the control power supply of the main important equipment in the coal and power production processes, and has good application prospects and guiding significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the electrical schematic diagram of the existing flame detector power supply cabinet;

[0025] Figure 2 is the wiring diagram of the power supply circuit of the existing flame detector power supply cabinet;

[0026] Figure 3 is the electrical schematic diagram of the A-side flame detector power supply cabinet of the embodiment of the present utility model;

[0027] Figure 4 is the wiring diagram of the power supply circuit of the A-side flame detector power supply cabinet of the embodiment of the present utility model;

[0028] Figure 5 is the electrical schematic diagram of the B-side flame detector power supply cabinet of the embodiment of the present utility model;

[0029] Figure 6 It is the wiring diagram of the power supply circuit of the B-side flame detector power cabinet in the embodiment of the present utility model. Specific embodiments

[0030] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the embodiments of the present utility model. Apparently, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts shall fall within the protection scope of the present utility model.

[0031] The technical solutions of the present utility model will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments:

[0032] Embodiment 1

[0033] As Figures 3-6 shown, specifically, a boiler flame detector power cabinet is disclosed, which includes an A-side power cabinet and a B-side power cabinet with the same structure; since the A-side power cabinet and the B-side power cabinet have the same structure, the A-side power cabinet will be taken as an example for detailed introduction:

[0034] The A-side power cabinet includes an A-side power supply circuit and an A-side flame detector power breaker; the A-side power supply circuit includes air switches QF1-2, intermediate relays KA1-5, power modules A1-2, and a switching power supply;

[0035] After the input ends of the power module A1 and the intermediate relay KA1 are connected in parallel, they are then connected to the output end of the air switch QF1, and the input end of the air switch QF1 is connected to the plant power supply; the output end of the intermediate relay KA1 sends a plant power supply fault alarm signal; the output end of the power module A1 and the input end of the intermediate relay KA3 are connected in parallel and then connected to the first input end of the switching power supply;

[0036] After the input ends of the power module A2 and the intermediate relay KA2 are connected in parallel, they are then connected to the output end of the air switch QF2, and the input end of the air switch QF2 is connected to the UPS power supply; the output end of the intermediate relay KA2 sends a UPS power supply fault alarm signal; the output end of the power module A2 and the input end of the intermediate relay KA4 are connected in parallel and then connected to the second input end of the switching power supply;

[0037] The output end of the switching power supply and the input end of the intermediate relay KA5 are connected in parallel and then connected to the A-side flame detector power breaker; the output end of the intermediate relay KA5 sends a switching power supply fault alarm signal.

[0038] The power supply modules A1 - 2 are power supply modules of the model CP - S.1 24 / 10.0 under ABB, with an input of 100 - 240VAC and an output of 24V - 28VDC; the relays KA1 - 5 are relays of the model RXM2LB2P7 under Schneider.

[0039] In this embodiment, the switching power supply is a 24V DC switching power supply, adopting the CP series switching power supply under ABB, with the model CP - C.1 - A - RU. It can input two 24V DC power supplies and output one 24V DC power supply, so that the loss of a single input power supply among the two input power supplies will not cause the output power supply to lose power. Compared with the half - bridge circuit coupling method used in the original power supply circuit, the diodes in the circuit will overheat and even be damaged during the long - term operation of the unit, resulting in the loss of the 24V power supply output, and then the unit trips. By using a switching power supply to replace the original half - bridge circuit to couple two input 24V DC power supplies, the utility model effectively eliminates the potential safety risk of the unit tripping due to the diode failure causing the full - furnace flame - out protection action.

[0040] In this embodiment, when a power failure occurs at the 220V plant power supply, the output end of the intermediate relay KA1 sends a plant power supply fault alarm signal to the DCS, and the DCS displays the alarm information to remind the operation and maintenance personnel, shortening the on - site power failure troubleshooting time and improving the reliability of equipment operation; similarly, when a power failure occurs at the 220V UPS power supply, the output end of the intermediate relay KA2 sends a UPS power supply fault alarm signal; when a power failure occurs at the 24V DC output of the switching power supply, the output end of the intermediate relay KA5 sends a switching power supply fault alarm signal.

[0041] As Figure 4 shown, the A - side flame detector power supply circuit breaker includes air switches QF4 - 9 and fuses FU1 - 30; after the input ends of the air switches QF4 - 6 are connected together, they are then connected to the output end of the switching power supply; the fuses FU1 - 6 are connected in parallel and then connected to the output end of the air switch QF4; the fuses FU7 - 12 are connected in parallel and then connected to the output end of the air switch QF5; the fuses FU13 - 18 are connected in parallel and then connected to the output end of the air switch QF6; the fuses FU19 - 21 are connected in parallel and then connected to the output end of the air switch QF7; the fuses FU22 - 27 are connected in parallel and then connected to the output end of the air switch QF8; the fuses FU28 - 30 are connected in parallel and then connected to the output end of the air switch QF9.

[0042] Working principle:

[0043] As Figure 3 、 Figure 5As shown in the figure, the power supply circuit structures of the A-side and B-side power cabinets are the same. The power supply circuits both adopt the plant-used power supply of 220V and the self-heat control UPS power supply of 220V, so that when a single 220V power supply is lost, it will not cause the power supply circuit to lose power and the flame detection power supply to lose power. The 220V alternating current is converted into 24V direct current through the power module. The input end of the switching power supply receives two paths of 24V direct current and stably outputs one path of 24V direct current power supply.

[0044] Referring to the fact that there are 6 burners arranged on each layer in the first phase of Panji Power Plant and the national electric power industry standard "DL / T1091-2018 Technical Regulations for Boiler Furnace Safety Monitoring System of Thermal Power Plants", it can be known that the criterion for the loss of flame detection protection of the coal layer burners is "six out of four", that is, among the 6 pulverized coal burners corresponding to the same coal mill, if 4 or more burners lose flame, the coal mill should be protected and tripped. In view of this, the present utility model designs two sets of flame detection power cabinets, namely the A-side and B-side power cabinets. As Figure 4 、 Figure 6 shown in the figure, the flame detection power circuit breakers of the A-side and B-side power cabinets have the same structure. The 24V direct current is output to three of the six flame detection probes corresponding to the six burners respectively through 6 air switches. Each flame detection probe power supply is independently designed. When the fuse of a single flame detection probe power supply circuit fails and blows, it can prevent the corresponding air switch from tripping. Among them, the A-side flame detection power circuit breaker is dedicated to the flame detection probes of burners No. 1, 2, and 3 of the corresponding coal layer, and the B-side flame detection power circuit breaker is dedicated to the flame detection probes of burners No. 4, 5, and 6 of the corresponding coal layer.

[0045] The present utility model optimizes and transforms the boiler flame detection dual-power switching device, and sends the power loss alarm of each power supply to the DCS, shortening the on-site power supply fault elimination time and improving the reliability of equipment operation;

[0046] The present utility model adopts a 24V DC switching power supply to replace the existing half-bridge circuit to couple two power supplies, so that when a single input power supply fails and the diode is damaged, the situation of the output power supply losing power can be avoided;

[0047] Based on the criterion of "six out of four" for the loss of flame detection protection of the coal layer burners, the present utility model arranges the A-side and B-side power cabinets to disperse the power consumption of the flame detection of each burner. The failure of a single-sided power cabinet will not cause the coal mill to trip due to the loss of flame detection and the MFT to be triggered due to the loss of flame detection in the whole furnace, greatly improving the safety and reliability of the flame detection power supply.

[0048] According to the calculation of the unplanned outage of the unit caused by the flame detection power supply failure once in two units in the first phase of Panji Power Plant, taking the unit unplanned outage of 5 hours as an example, the following table is for calculating the economic losses caused by the unit unplanned outage:

[0049] 1. According to the relevant provisions of the "Implementation Rules for the Grid-connected Operation Management of Power Plants in East China", if a normally operating generator set suddenly trips, the power consumption shall be assessed each time:

[0050]

[0051] In the formula, Q 非停 To evaluate the power, P N is the unit capacity (MW), is the unit shutdown hours (hours), the maximum is 72 hours, α 非停 It is the assessment coefficient of unplanned outage, and its value is 0.2. If the outage lasts for 5 hours, the assessment power consumption is:

[0052] Q 非停 =0.5×660×1000×5×0.2=330000kW·h

[0053] 2. From the time the unit trips to the time the cause of the trip is identified and the unit is ready to restart, during this period of time, assuming 5 hours and a unit load of 660MW, the power loss is approximately:

[0054] Q=5×660×1000=3300000kW·h

[0055] The total amount of oil and water consumed during the restart of the unit is about 1 million yuan. At the same time, the burning of oil during the restart will cause environmental pollution, which is not in line with energy conservation and emission reduction.

[0056] Table 1 is an economic summary of the losses caused by non-stop operation of a primary unit:

[0057] Table 1 Economic summary of losses caused by non-stop operation of primary units

[0058]

[0059] The economic benefit of this transformation is 2.481 million yuan. It can be seen that the utility model enables the two units of the first phase of Panji Power Plant to save about 2.481 million yuan in cost during their service life.

[0060] The utility model has low transformation investment cost and obvious effect, and high safety benefits are achieved after the transformation, thereby improving the safety of unit operation.

[0061] The power supply circuit designed by the utility model is simple in design and highly reliable, and is suitable for the design of power control circuits for various important industrial production equipment, especially the control power of main important equipment in the process of coal and electricity production, and has good application prospects and guiding significance.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A boiler fire detection power supply cabinet, characterized in that: It includes an A-side power supply cabinet and a B-side power supply cabinet with the same structure; the A-side power supply cabinet includes an A-side power supply circuit and an A-side fire detection power supply circuit breaker; the A-side power supply circuit includes air switches QF1-2, intermediate relays KA1-5, power modules A1-2, and a switching power supply; The input end of the power module A1 is connected in parallel with the input end of the intermediate relay KA1, and then connected to the output end of the idle switch QF1, and the input end of the idle switch QF1 is connected to the factory power supply; the output end of the power module A1 is connected in parallel with the input end of the intermediate relay KA3, and then connected to the first input end of the switching power supply; The input end of the power module A2 is connected in parallel with the input end of the intermediate relay KA2, and then connected to the output end of the idle switch QF2, and the input end of the idle switch QF2 is connected to the UPS power supply; The output end of the power module A2 is connected in parallel with the input end of the intermediate relay KA4, and then connected to the second input end of the switching power supply; the output end of the switching power supply is connected in parallel with the input end of the intermediate relay KA5, and then connected to the A-side fire detection power supply circuit breaker; The A-side fire detection power supply circuit breaker includes air switches QF4~9 and fuses FU1~30; the input ends of the air switches QF4~6 are connected together and then connected to the output end of the switching power supply; the fuses FU1~6 are connected in parallel and then connected to the output end of the air switch QF4; the fuses FU7~12 are connected in parallel and then connected to the output end of the air switch QF5; the fuses FU13~18 are connected in parallel and then connected to the output end of the air switch QF6; the fuses FU19-21 are connected in parallel and then connected to the output end of the air switch QF7; the fuses FU22~27 are connected in parallel and then connected to the output end of the air switch QF8; the fuses FU28~30 are connected in parallel and then connected to the output end of the air switch QF9.

2. A boiler fire detection power supply cabinet according to claim 1, characterized in that: The output end of the intermediate relay KA1 sends a factory power failure alarm signal.

3. A boiler fire detection power supply cabinet according to claim 1, characterized in that: The output end of the intermediate relay KA2 sends a UPS power failure alarm signal.

4. A boiler fire detection power supply cabinet according to claim 1, characterized in that: The output end of the intermediate relay KA5 sends a switching power supply failure alarm signal.

5. A boiler fire detection power supply cabinet according to claim 1, characterized in that: The switching power supply model is CP-C.1-A-RU.

6. A boiler fire detection power supply cabinet according to claim 1, characterized in that: The factory power supply and UPS power supply are both 220V.

7. A boiler fire detection power supply cabinet according to claim 1, characterized in that: The model of the power modules A1-2 is CP-S.1 24 / 10.

0.

8. A boiler fire detection power supply cabinet according to claim 1, characterized in that: The model of the relays KA1-5 is RXM2LB2P7.

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