Emergency oil discharge device, control system and method for ultra-high voltage converter transformer

Abstract

An emergency oil discharge device, control system and method for a UHV converter transformer belong to the field of emergency oil discharge for UHV converter transformers, and include a body tee, a shutoff valve, a body oil tank oil discharge device, an oil storage cabinet oil discharge device and an accident oil pool; the body tee is arranged between the upper part of the body oil tank and the bottom of the oil storage cabinet, the first port of the body tee is connected to the bottom of the oil storage cabinet through a pipeline, the second port is connected to the oil storage cabinet oil discharge device through a pipeline, the third port is provided with a shutoff valve, the output port of the shutoff valve is connected to the body oil tank through a pipeline, the body oil tank oil discharge device is connected to the bottom of the body oil tank through a pipeline, and the output ends of the body oil tank oil discharge device and the oil storage cabinet oil discharge device are respectively connected to the accident oil pool through pipelines; when draining oil, the shutoff valve is closed to cut off the oil supply pipeline from the oil storage cabinet to the body oil tank, the body oil tank oil discharge device and the oil storage cabinet oil discharge device discharge oil independently, and the transformer oil in the body oil tank and the oil storage cabinet is quickly discharged when an initial fire occurs.

Description

Technical Field

[0001] The present invention belongs to the field of emergency oil discharge of ultra-high voltage converter transformers, and in particular relates to an emergency oil discharge device, a control system and a method for ultra-high voltage converter transformers. Background Art

[0002] Ultra-high voltage refers to voltage levels of 1000 kV and above for AC and 800 kV and above for DC. The main characteristics of ultra-high voltage transmission are high voltage, large transmission capacity, and narrow line corridors, making it suitable for high-power and long-distance power transmission.

[0003] A converter station is a system for mutual energy conversion between DC and AC in UHV power transmission projects. In addition to the AC field and other equipment that are the same as those in an AC substation, a converter station also has the following equipment: converters, converter transformers, AC / DC filters and reactive power compensation equipment, smoothing reactors, etc.

[0004] The converter transformer is a critical equipment in UHV power transmission projects. It is the core equipment of the interfaces between the rectifier and inverter in AC and DC power transmission systems. The converter transformer belongs to oil-immersed transformer. The transformer oil filled in the oil tank of the oil-immersed transformer is a hydrocarbon liquid mixture mainly composed of cycloalkyl groups extracted from crude oil. It is usually divided into -25 (condensation point) and -45 transformer oils, and -25 is commonly used. The initial distillation point of the transformer oil is greater than 300°C. When it leaves the factory, its flash point is above 140°C. After being filled into the transformer and working for a long time, due to local high temperature and high voltage cracking, a small amount of hydrogen and light hydrocarbons will be produced, causing gaseous combustibles to mix into the gas phase space.

[0005] Through the analysis of several oil-immersed transformer fire cases at home and abroad, the fire modes of oil-immersed transformers can be divided into three categories: initial insulator root burst fire, partial oil tank burst fire, and overall oil tank burst fire. Among them, the initial insulator root burst fire is the main one, and the partial oil tank burst fire is mostly developed from the insulator root fire. The overall oil tank burst fire is relatively rare. Since the gas phase space in the insulator is most likely to produce electric sparks, and the insulator is the weakest part of the oil-immersed transformer, the initial fire of the oil-immersed transformer is mostly manifested as an explosion and fire at the root of the insulator. When the oil of the oil-immersed transformer catches fire, the oil is mostly at a high temperature, and when the fire extinguishing system is activated, it has often been burning for a certain period of time, causing the metal structure to be heated to a high temperature. Therefore, the main characteristics of the oil-immersed transformer fire are the combined effect of oil fire and high-temperature metal structure.

[0006] The converter transformers used in the UHV power transmission field contain a large amount of transformer oil. The oil storage capacity inside the main body oil tank of my country's UHV converter transformers in operation is about 130 to 200 tons, and the oil storage capacity of the oil storage cabinet is generally 10 to 30 tons. Most of the models are Kunlun KI50X. The oil storage cabinet is connected to the main body oil tank through a valve. Therefore, the oil storage capacity inside the entire converter transformer is about 140 to 230 tons. When an explosion and fire occurs at the root of the bushing insulator on the grid side, it will cause secondary damage to the UHV converter transformer oil tank. A gap will be blown in the converter transformer oil tank, and a large amount of transformer oil will overflow through the gap under the action of gravity, flow through the complex surface of the transformer and be partially ignited. The complex vertical flow formed provides a continuous fuel supply for the external fire source of the transformer, causing continuous combustion. At the same time, the external ignited transformer oil fire heats the transformer body, causing the internal oil temperature of the transformer to increase. The transformer oil expands in volume due to thermal expansion and contraction, further increasing the amount of oil leaking to the outside, causing the fire to further deteriorate and get out of control, and it is almost impossible to be covered by the fire extinguishing agent. This is one of the fundamental reasons why fires in converter transformers for UHV transmission are difficult to extinguish.

[0007] Therefore, when a fire accident occurs in a UHV converter transformer, it is very necessary to drain the large amount of transformer oil inside the converter transformer into the accident oil pool, thereby reducing the possibility of fire getting out of control, reducing the difficulty of fire fighting, and improving the success rate of fire extinguishing.

[0008] In the prior art, the Chinese invention patent application "High-temperature flame-retardant combined valve control system for accident oil drain pipeline of ultra-high voltage transformer" with application publication date of November 13, 2018 and application publication number CN108806932A discloses a high-temperature flame-retardant combined valve control system for accident oil drain pipeline of ultra-high voltage transformer. The system blocks the oil drain pipeline when the oil level is low and opens the pipeline to drain oil when the oil level is high by setting a comprehensive pipeline control mechanism and a one-way valve, thereby realizing real-time control of the oil level in the oil drain pipe, and realizing the connection of the pipeline by rotating the valve in the annular cross-section of the oil drain pipe left or right around the axis.

[0009] The above-mentioned Chinese patent application has the following shortcomings:

[0010] (1) The oil conservator and the main oil tank share a set of oil drainage system, which takes too long to drain and cannot meet the actual needs of the site;

[0011] (2) Fire-blocking design was only carried out for the oil-draining pool to the accident oil pool, but not for the entire system. During the oil discharge process, the flames, along with a large amount of unburned flammable steam and unpremixed air, would enter the draining oil pipe, causing the fire to spread in the oil pipe;

[0012] (3) All valves are designed in series, and the system reliability is not high. If a single valve fails and cannot be opened, the system will not be able to drain oil.

[0013] Therefore, when an initial fire occurs in a UHV converter transformer, how to quickly, safely and reliably discharge the large amount of transformer oil inside the main oil tank and oil storage cabinet is an urgent problem to be solved. Summary of the invention

[0014] The technical problem to be solved by the present invention is how to quickly, safely and reliably discharge a large amount of transformer oil inside the main body oil tank and the oil storage cabinet when an initial fire occurs in a UHV converter transformer.

[0015] The present invention solves the above technical problems through the following technical solutions.

[0016] An emergency oil discharge device for a UHV converter transformer is used for discharging oil from a converter transformer body oil tank (1) and an oil storage cabinet (10), comprising a body tee (11), a stop valve (12), a body oil tank oil discharge device, an oil storage cabinet oil discharge device and an emergency oil pool; the body tee (11) is arranged between the upper part of the body oil tank (1) and the bottom of the oil storage cabinet (10); the first port of the body tee (11) is connected to the bottom of the oil storage cabinet through a pipeline, the second port is connected to the oil storage cabinet oil discharge device through a pipeline, and the third port is arranged A stop valve (12), the output port of the stop valve (12) is connected to the main body oil tank (1) through a pipeline, the main body oil tank oil discharge device is connected to the bottom of the main body oil tank (1) through a pipeline, and the output ends of the main body oil tank oil discharge device and the oil storage cabinet oil discharge device are respectively connected to the accident oil pool through pipelines; when oil discharge is required, the stop valve (12) is closed to cut off the oil supply pipeline from the oil storage cabinet (10) to the main body oil tank (1), and the main body oil tank oil discharge device and the oil storage cabinet oil discharge device respectively and independently discharge oil to the accident oil pool.

[0017] When the emergency oil discharge device of the UHV converter transformer receives the oil discharge start signal, it closes the shut-off valve and cuts off the explosion-proof flame arrester oil discharge pipeline from the oil storage cabinet to the main oil tank. The main oil tank and the oil storage cabinet each use a set of oil discharge devices to independently discharge the oil. The oil in the oil storage cabinet no longer enters the main oil tank, and the oil discharge time is greatly shortened, preventing the transformer oil from continuously overflowing and burning. After the main oil tank is completely drained, the solid insulation inside the transformer is smaller than the fire caused by the leakage of oil and gas, which can effectively prevent the oil-fire mixture from flowing into the valve hall after the bushing on the valve side of the converter transformer is burned, thereby avoiding the fire from spreading.

[0018] As a further improvement of the technical solution of the present invention, the main body oil tank oil discharge device comprises a check valve (2), a first oil flow meter (3), a first double-phase electric valve group (4), a plurality of main body oil tank leakage alarms (5), and a plurality of main body oil tank butterfly valves (6); the main body oil tank (1), the check valve (2), the first oil flow meter (3), the first double-phase electric valve group (4), a plurality of main body oil tank leakage alarms (5), and a plurality of main body oil tank butterfly valves (6) are connected to the accident oil pool in sequence through pipelines along the negative direction of the x-axis.

[0019] As a further improvement of the technical solution of the present invention, the oil storage tank oil discharge device comprises a second double-double ...

[0020] As a further improvement of the technical solution of the present invention, the first double-combination electric valve group (4) includes two normally closed butterfly valves. After the two normally closed butterfly valves are connected in parallel, one end is connected to the first oil flow meter (3) through a pipeline, and the other end is connected to the main oil tank leakage alarm (5) through a pipeline. The power supply circuit and control circuit of each normally closed butterfly valve are independently powered.

[0021] As a further improvement of the technical solution of the present invention, the second double-combination electric valve group (13) includes two normally closed butterfly valves, which are connected in parallel and have one end connected to a second oil flow meter (14) through a pipeline, and the other end connected to an oil storage tank leakage alarm (15) through a pipeline.

[0022] As a further improvement of the technical solution of the present invention, the pipeline adopts an anti-explosion type flame arrester oil discharge pipeline.

[0023] A control system applied to an emergency oil discharge device of an ultra-high voltage converter transformer comprises an oil discharge control cabinet, a first control center and a second control center. The oil discharge control cabinet integrates a first oil discharge control unit and a second oil discharge control unit; the first control center is respectively connected to the first oil discharge control unit and the second oil discharge control unit; the second control center is respectively connected to the first oil discharge control unit and the second oil discharge control unit; the first oil discharge control unit is respectively connected to a main body oil tank oil discharge device, an oil storage tank oil discharge device and a shut-off valve (12) by hard wiring; the second oil discharge control unit is respectively connected to a main body oil tank oil discharge device, an oil storage tank oil discharge device and a shut-off valve (12) by hard wiring.

[0024] As a further improvement of the technical solution of the present invention, the first control center or the second control center sends an oil discharge start signal, and the signal is transmitted to the first oil discharge control unit and the second oil discharge control unit at the same time. The first oil discharge control unit transmits the signal to the main body oil discharge device, the oil storage tank oil discharge device and the cut-off valve (12) respectively; at the same time, the second oil discharge control unit transmits the signal to the main body oil discharge device, the oil storage tank oil discharge device and the cut-off valve (12) respectively; the cut-off valve (12) is controlled to be closed, and the main body oil discharge device and the oil storage tank oil discharge device are opened to discharge the converter oil to the accident oil pool.

[0025] As a further improvement of the technical solution of the present invention, the hard wiring is a high temperature resistant and flame retardant armored shielded cable.

[0026] A control method based on the control system comprises the following steps:

[0027] 1) The first control center or the second control center powers on the system and sends an oil discharge start signal to the oil discharge control cabinet, at which time the oil discharge control cabinet controls the shutoff valve (12) to close, thereby cutting off the pipeline connecting the oil storage cabinet (10) to the main body oil tank (1);

[0028] 2) After the main body oil tank oil discharge device receives the oil discharge start signal sent by the oil discharge control cabinet, the main body oil tank (1) starts to discharge oil, and the oil discharge control cabinet starts timing at this time;

[0029] 3) After the accumulated timing reaches 10s, the oil discharge control cabinet sends an oil discharge start signal to the oil discharge device of the oil storage cabinet. After receiving the oil discharge start signal, the oil discharge device of the oil storage cabinet starts to discharge the oil;

[0030] 4) When the oil level of the converter transformer main body oil tank (1) reaches the oil draining end threshold, the oil draining process of the main body oil tank oil draining device and the oil storage cabinet oil draining device ends.

[0031] As a further improvement of the technical solution of the present invention, the method for generating the oil discharge start signal comprises the following steps:

[0032] 1) The oil discharge control cabinet receives the heavy gas signal, fire alarm signal and transformer power-off signal, performs the logic “AND” operation on the three signals and outputs them; the output logic “AND” signal is sent to the first control center and the second control center;

[0033] 2) The first control center or the second control center reports and requests instructions based on the on-site situation and eliminates interference such as false alarms and small-scale fires. After comprehensive judgment and processing, the first control center or the second control center issues an oil discharge start signal and transmits it to the oil discharge control cabinet.

[0034] As a further improvement of the technical solution of the present invention, the oil discharge start signal adopts a remote manual electrical start method.

[0035] The advantages of the present invention are:

[0036] (1) When the emergency oil discharge device of the UHV converter transformer receives the oil discharge start signal, it closes the shut-off valve and cuts off the explosion-proof flame arrester oil discharge pipeline from the oil storage cabinet to the main oil tank. The main oil tank and the oil storage cabinet each use a set of oil discharge devices to independently discharge the oil. The oil in the oil storage cabinet no longer enters the main oil tank, and the oil discharge time is greatly shortened, preventing the transformer oil from continuously overflowing and burning. After the main oil tank is completely drained, the solid insulation inside the transformer is smaller than the fire caused by the leakage of oil and gas, which can effectively prevent the oil-fire mixture from flowing into the valve hall after the bushing on the converter transformer valve side is burned, thereby avoiding the fire from spreading.

[0037] (2) The dual-configuration electric valve groups of the main oil tank drain device and the oil storage cabinet drain device are opened successively to drain the oil. Even if a single valve fails, the oil drain system can still drain the oil normally, with high reliability.

[0038] (3) The use of anti-explosion flame arrester oil discharge pipeline effectively prevents the flame from entering the empty oil pipe along with a large amount of unburned combustible steam and unpremixed air during the oil discharge process, causing the fire to spread in the oil pipe, which is highly safe.

[0039] (4) The first oil discharge control unit and the second oil discharge control unit are cross-connected with the first control center and the second control center of the duplex system. The duplex electric valve group of the main oil tank oil discharge device and the oil storage cabinet oil discharge device are controlled by hard wiring. The two sets of oil discharge control units operate independently without distinction between the primary and the standby, thereby preventing the situation in which the duplex electric valve group cannot be started due to a failure of one of the oil discharge control units.

[0040] (5) The oil discharge start signal adopts remote manual electrical start. When the oil discharge system needs to be started, the operator confirms the on-site situation and double confirms it on the remote control panel or in the operation box before starting. This prevents huge losses caused by system malfunctions due to interference signals such as false alarms and small-scale fire alarms.

[0041] (6) The oil discharge pipeline passes through the pebble layer and directly leads to the accident oil pool. The oil discharge test has verified that the flaming oil will not be injected into the accident oil pool.

[0042] (7) The monitoring circuit of the converter oil discharge system is powerful. The monitoring signals include power failure signal of the electric ball valve power supply and control power supply, open / close status signal, oil leakage signal of the oil discharge pipeline, etc., which can be monitored in real time.

[0043] (8) The cable is designed with fire-resistant cable and fireproof cover, and the electric ball valve is fully protected by the fireproof cover, which can ensure that the oil can be remotely opened and drained after direct combustion for 1 hour. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a structural diagram of the main body oil tank oil discharge device of an embodiment of the present invention;

[0045] Figure 2 This is a structural diagram of an oil conservator oil discharge device according to an embodiment of the present invention;

[0046] Figure 3 is a block diagram of an emergency oil discharge system according to an embodiment of the present invention;

[0047] Figure 4 A control system diagram of an emergency oil discharge system according to an embodiment of the present invention;

[0048] Figure 5 A logic diagram for generating an emergency oil discharge start signal according to an embodiment of the present invention;

[0049] Figure 6 This is a startup process of an emergency oil discharge system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0052] Example

[0053] like Figure 1 and Figure 2 As shown, an emergency oil discharge device for a UHV converter transformer comprises an oil discharge device for a main body oil tank 1 and an oil discharge device for an oil storage cabinet 10. The oil discharge device for the main body oil tank 1 comprises a check valve 2, a first oil flow meter 3, a first double-divided electric valve group 4, a plurality of main body oil tank leakage alarms 5, a plurality of main body oil tank butterfly valves 6, and an accident oil pool. The oil discharge device for the oil storage cabinet 10 comprises a main body tee 11, a stop valve 12, a second double-divided electric valve group 13, a second oil flow meter 14, a plurality of oil storage cabinet leakage alarms 15, and a plurality of oil storage cabinet butterfly valves 16.

[0054] like Figure 1 As shown, the main body oil tank 1, the inspection valve 2, the first oil flow meter 3, the first double-duty configuration electric valve group 4, multiple main body oil tank leakage alarms 5, and multiple main body oil tank butterfly valves 6 are connected to the accident oil pool in sequence along the negative direction of the x-axis through the anti-explosion type flame arrester oil discharge pipeline.

[0055] The first double-combination electric valve group 4 includes two normally closed butterfly valves. After the two normally closed butterfly valves are connected in parallel, one end is connected to the first oil flow meter 3 through the anti-explosion type flame arrester oil discharge pipeline, and the other end is connected to the main body oil tank leakage alarm 5 through the anti-explosion type flame arrester oil discharge pipeline.

[0056] Preferably, the two main body oil tank leakage alarms 5 and the two main body oil tank butterfly valves 6 are staggeredly connected along the negative direction of the x-axis through the deflagration-resistant flame arrester oil discharge pipeline.

[0057] like Figure 2 As shown, the oil storage cabinet 10, the main body three-way 11, the second double-combined electric valve group 13, the second oil flow meter 14, multiple oil storage cabinet leakage alarms 15, and multiple oil storage cabinet butterfly valves 16 are connected to the accident oil pool in sequence along the negative direction of the y-axis through the anti-explosion type flame arrester oil discharge pipeline.

[0058] The first port of the main body tee 11 is connected to the oil storage cabinet 10 through the anti-explosion type flame arrester oil discharge pipeline, the second port is connected to the second double-combination electric valve group 13 through the anti-explosion type flame arrester oil discharge pipeline, and the third port output port is provided with a stop valve 12, and the output port of the stop valve 12 is connected to the main body oil tank 1 through the anti-explosion type flame arrester oil discharge pipeline.

[0059] The second double-combination electric valve group 13 includes two normally closed butterfly valves. After the two normally closed butterfly valves are connected in parallel, one end is connected to the second oil flow meter 14 through the anti-explosion type flame arrester oil discharge pipeline, and the other end is connected to the oil storage cabinet leakage alarm 15 through the anti-explosion type flame arrester oil discharge pipeline.

[0060] Preferably, the two oil storage tank leakage alarms 15 and the two oil storage tank butterfly valves 16 are staggeredly connected along the negative direction of the x-axis through the deflagration-resistant flame arrester oil discharge pipeline.

[0061] The first oil flow meter 3 and the second oil flow meter 14 are used to monitor the flow of the converter oil in the oil discharge pipeline of the deflagration-resistant flame arrester in real time.

[0062] The first double-phase configuration electric valve group 4 and the second double-phase configuration electric valve group 13, after the control system sends a signal to the oil discharge device of the main oil tank 1 or the oil discharge device of the oil storage cabinet 10, the first double-phase configuration electric valve group 4 or the second double-phase configuration electric valve group 13 changes from normally closed to normally open and enters the oil discharge mode; the two normally closed butterfly valves of the first double-phase configuration electric valve group 4 and the second double-phase configuration electric valve group 13 each include an independent power supply circuit and a control circuit, and the power supply of the power supply circuit of each normally closed butterfly valve adopts a 220V single-phase AC power supply, which is respectively taken from different bus sections of the station AC system, and the control power supply of the control circuit of each normally closed butterfly valve is respectively taken from the station 110V DC section 1 and section 2, so as to avoid the situation where a section of the DC bus loses voltage or the DC is grounded, resulting in the two normally closed butterfly valves being unable to work normally at the same time.

[0063] The main body oil tank leakage alarm 5 and the oil storage cabinet leakage alarm 15 are used to monitor in real time whether there is leakage in the oil discharge pipeline of the anti-explosion flame arrester when the converter transformer is in normal operation or emergency oil discharge.

[0064] The deflagration-resistant flame arrester oil discharge pipeline has a wall effect, a heat conduction effect, and a flame obstruction effect, which prevents the flame during the oil discharge process from entering the empty oil pipe together with a large amount of unburned combustible steam and unpremixed air to cause the fire to spread in the oil pipe.

[0065] like Figure 3 As shown, the emergency oil discharge system of the UHV converter transformer includes a control system, a main body oil tank oil discharge device, an oil storage cabinet oil discharge device, and a shut-off valve 12. The control system controls the start and close of the main body oil tank oil discharge device, the oil storage cabinet oil discharge device, and the shut-off valve 12 according to the oil discharge start signal.

[0066] like Figure 4 As shown, the control system includes an oil discharge control cabinet, a control center A, and a control center B. The oil discharge control cabinet integrates an oil discharge control unit A and an oil discharge control unit B; the control center A is respectively connected to the oil discharge control unit A and the oil discharge control unit B through IEC61850 communication; the control center B is respectively connected to the oil discharge control unit A and the oil discharge control unit B through IEC61850 communication; the oil discharge control unit A is respectively connected to the first double-dimensioned electric valve group 4 of the main oil tank oil discharge device, the second double-dimensioned electric valve group 13 of the oil storage cabinet oil discharge device, and the shut-off valve 12 through hard wiring; the oil discharge control unit B is respectively connected to the first double-dimensioned electric valve group 4 of the main oil tank oil discharge device, the second double-dimensioned electric valve group 13 of the oil storage cabinet oil discharge device, and the shut-off valve 12 through hard wiring.

[0067] Control center A or control center B reports and requests instructions after eliminating interferences such as false alarms and small-scale fires according to the on-site situation. After comprehensive judgment and processing, control center A or control center B remotely and manually sends an oil discharge start signal, and the signal is transmitted to the oil discharge control unit A and the oil discharge control unit B at the same time. The oil discharge control unit A transmits the signal to the first double-chemical configuration electric valve group 4 of the main body oil discharge device, the second double-chemical configuration electric valve group 13 of the oil storage tank oil discharge device, and the shut-off valve 12 respectively; at the same time, the oil discharge control unit B transmits the signal to the first double-chemical configuration electric valve group 4 of the main body oil discharge device, the second double-chemical configuration electric valve group 13 of the oil storage tank oil discharge device, and the shut-off valve 12 respectively; the shut-off valve 12 is controlled to be closed, and the first double-chemical configuration electric valve group 4 and the second double-chemical configuration electric valve group 13 are started to discharge the converter oil to the accident oil pool.

[0068] The oil discharge control unit A and the oil discharge control unit B are cross-connected with the duplicated control center A and the control center B. The duplicated electric valve group of the main oil tank oil discharge device and the oil storage cabinet oil discharge device are controlled through hard wiring. The two sets of oil discharge control units operate independently without distinction between primary and standby, to prevent the situation where the duplicated electric valve group cannot be started due to a failure of one of the oil discharge control units.

[0069] The main body oil tank oil discharge device and the oil storage cabinet oil discharge device are both provided with monitoring circuits for monitoring the power supply failure signal, control power supply failure signal, valve open / close state signal, and oil discharge pipeline leakage signal of the dual configuration electric valve group.

[0070] like Figure 5 As shown, the method for generating the oil discharge start signal comprises the following steps:

[0071] 1) The oil discharge control cabinet receives the heavy gas signal (two out of three), the fire alarm signal (at least two fire alarm signals) and the transformer power-off signal, performs the logic "AND" operation on the three signals and outputs them; the output logic "AND" signal is sent to the control center A and the control center B.

[0072] 2) Control Center A or Control Center B reports and requests instructions based on the on-site situation and eliminates interference such as false alarms and small-scale fires. After comprehensive judgment and processing, Control Center A or Control Center B remotely and manually sends an oil discharge start signal to the oil discharge control unit.

[0073] The oil discharge start signal adopts a remote manual electrical start mode to prevent huge losses caused by system malfunction due to interference signals such as false alarms and small-scale fire alarms.

[0074] like Figure 6As shown, the start-up process of the main oil tank oil discharge device and the oil conservator oil discharge device of the emergency oil discharge system of the UHV converter transformer is that the control center A or the control center B powers on the system and sends an oil discharge start signal to the oil discharge control cabinet. At this time, the oil discharge control cabinet controls the shut-off valve 12 to close, and cuts off the pipeline from the oil conservator 10 to the main oil tank 1; after the main oil tank oil discharge device receives the oil discharge start signal, the two normally closed butterfly valves of the first double-double ... Since the amount of oil inside the oil storage cabinet 10 is much smaller than the amount of oil in the main body oil tank 1, when the oil level in the converter transformer main body oil tank 1 reaches the oil drainage end threshold (the oil level gauge in the converter transformer main body oil tank reaches the limit value), the dual configuration electric valve group is closed, and the oil drainage process of the main body oil tank oil drainage device and the oil storage cabinet oil drainage device is completed.

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An emergency oil discharge device for a UHV converter transformer, used for discharging oil from a converter transformer body oil tank (1) and an oil storage cabinet (10), characterized in that: The invention comprises a body tee (11), a stop valve (12), a body oil tank oil discharge device, an oil storage cabinet oil discharge device and an accident oil pool; the body tee (11) is arranged between the upper part of the body oil tank (1) and the bottom of the oil storage cabinet (10); the first port of the body tee (11) is connected to the bottom of the oil storage cabinet through a pipeline; the second port is connected to the oil storage cabinet oil discharge device through a pipeline; the third port is provided with a stop valve (12); the output port of the stop valve (12) is connected to the body oil tank (1) through a pipeline; the body oil tank oil discharge device is connected to the bottom of the body oil tank (1) through a pipeline; the output ends of the body oil tank oil discharge device and the oil storage cabinet oil discharge device are respectively connected to the accident oil pool through pipelines; when draining oil, the stop valve (12) is closed to cut off the oil supply pipeline from the oil storage cabinet (10) to the body oil tank (1); the body oil tank oil discharge device and the oil storage cabinet oil discharge device respectively and independently discharge oil to the accident oil pool; The main body oil tank oil discharge device comprises a check valve (2), a first oil flow meter (3), a first double-double ... The oil conservator oil discharge device comprises a second double-double ... The first double-combined electric valve group (4) comprises two normally closed butterfly valves, which are connected in parallel, one end of which is connected to the first oil flow meter (3) through a pipeline, and the other end of which is connected to the main body oil tank leakage alarm (5) through a pipeline, and the power supply circuit and control circuit of each normally closed butterfly valve are independently powered.

2. The emergency oil discharge device for ultra-high voltage converter transformer according to claim 1, characterized in that: The second double-combination electric valve group (13) comprises two normally closed butterfly valves, which are connected in parallel and have one end connected to a second oil flow meter (14) via a pipeline, and the other end connected to an oil storage tank leakage alarm (15) via a pipeline.

3. The emergency oil discharge device for ultra-high voltage converter transformer according to claim 1, characterized in that: The pipeline is an anti-explosion type flame arrester oil discharge pipeline.

4. A control system applied to the emergency oil discharge device of the UHV converter transformer according to any one of claims 1 to 3, characterized in that: The invention comprises an oil discharge control cabinet, a first control center and a second control center, wherein the oil discharge control cabinet integrates a first oil discharge control unit and a second oil discharge control unit; the first control center is respectively connected to the first oil discharge control unit and the second oil discharge control unit; the second control center is respectively connected to the first oil discharge control unit and the second oil discharge control unit; the first oil discharge control unit is respectively connected to a main body oil tank oil discharge device, an oil storage tank oil discharge device and a stop valve (12) by means of hard wiring; the second oil discharge control unit is respectively connected to a main body oil tank oil discharge device, an oil storage tank oil discharge device and a stop valve (12) by means of hard wiring.

5. The control system of the emergency oil discharge device of the UHV converter transformer according to claim 4 is characterized in that: The first control center or the second control center sends an oil discharge start signal, and the signal is transmitted to the first oil discharge control unit and the second oil discharge control unit at the same time; the first oil discharge control unit transmits the signal to the main body oil discharge device, the oil storage tank oil discharge device and the cut-off valve (12) respectively, and the second oil discharge control unit transmits the signal to the main body oil discharge device, the oil storage tank oil discharge device and the cut-off valve (12) respectively; the cut-off valve (12) is closed, the main body oil discharge device and the oil storage tank oil discharge device are opened, and the converter oil is discharged to the accident oil pool.

6. The control system of the emergency oil discharge device of the UHV converter transformer according to claim 4 is characterized in that: The hard wiring is a high temperature resistant flame retardant armored shielded cable.

7. A control method based on the control system according to any one of claims 4 to 5, characterized in that: The following steps are involved: 1) The first control center or the second control center powers on the system and sends an oil discharge start signal to the oil discharge control cabinet, at which time the oil discharge control cabinet controls the shutoff valve (12) to close, thereby cutting off the pipeline connecting the oil storage cabinet (10) to the main body oil tank (1); 2) After the main body oil tank oil discharge device receives the oil discharge start signal from the oil discharge control cabinet, the main body oil tank (1) starts to discharge oil, and the oil discharge control cabinet starts timing at this time; 3) After the accumulated timing reaches 10s, the oil discharge control cabinet sends an oil discharge start signal to the oil discharge device of the oil storage cabinet. After receiving the oil discharge start signal, the oil discharge device of the oil storage cabinet starts to discharge the oil; 4) When the oil level of the converter transformer main body oil tank (1) reaches the oil draining end threshold, the oil draining process of the main body oil tank oil draining device and the oil storage cabinet oil draining device ends.

8. The control system method of the UHV converter transformer emergency oil discharge device according to claim 7, characterized in that: The method for generating the oil discharge start signal comprises the following steps: 1) The oil discharge control cabinet receives the heavy gas signal, fire alarm signal and transformer power-off signal, performs the logic "AND" operation on the three signals and outputs them; the output logic "AND" signal is sent to the first control center and the second control center; 2) The first control center or the second control center reports and requests instructions based on the on-site situation and eliminates interference such as false alarms and small-scale fires. After comprehensive judgment and processing, the first control center or the second control center issues an oil discharge start signal and transmits it to the oil discharge control cabinet.

9. The control system method of the UHV converter transformer emergency oil discharge device according to claim 7, characterized in that: The oil discharge start signal adopts a remote manual electrical start mode.

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