CN112260198A - Multifunctional rail transit direct-current online ice melting system and method - Google Patents
Multifunctional rail transit direct-current online ice melting system and method Download PDFInfo
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- CN112260198A CN112260198A CN202011039051.7A CN202011039051A CN112260198A CN 112260198 A CN112260198 A CN 112260198A CN 202011039051 A CN202011039051 A CN 202011039051A CN 112260198 A CN112260198 A CN 112260198A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G7/00—Overhead installations of electric lines or cables
- H02G7/16—Devices for removing snow or ice from lines or cables
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60M—POWER SUPPLY LINES, AND DEVICES ALONG RAILS, FOR ELECTRICALLY- PROPELLED VEHICLES
- B60M3/00—Feeding power to supply lines in contact with collector on vehicles; Arrangements for consuming regenerative power
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Abstract
The invention provides a multifunctional rail transit direct-current online ice melting system and method. The system comprises a direct-current online ice melting device, wherein the direct-current online ice melting device is installed at a middle station of a line needing ice melting, the middle station comprises a step-down substation, the head and tail station of the line needing ice melting is a traction substation, the alternating-current input of the direct-current online ice melting device is connected with a three-phase alternating-current power grid, the positive pole of a direct-current output is connected to the midpoint of an uplink catenary of the line needing ice melting, the negative pole of the direct-current output is connected to the midpoint of a downlink catenary of the line needing ice melting, the direct-current online ice melting device and the uplink and downlink catenary of the line needing ice melting form an ice melting path together, and direct-current online ice melting. The ice melting of the contact net is realized under the condition that the power supply of the contact net is not influenced, the ice coating of the contact net can be prevented, and the condition that the contact net is coated with ice again in a short time after the ice melting of the contact net is avoided; has the function of recovering the regenerative braking energy of the train.
Description
Technical Field
The invention relates to the technical field of rail transit safety control, in particular to a multifunctional rail transit direct-current online ice melting system and method.
Background
As an important infrastructure related to the national civilization, the urban rail transit is easy to cause the icing phenomenon of a contact net on the ground and on lines in a vehicle section under the climatic conditions of low temperature, freezing rain, wet snow, freezing and the like. When the contact line is covered with ice, an arc discharge phenomenon is generated between the contact line and the pantograph, so that the train cannot normally take current, the network pressure is unstable, even serious accidents such as line breakage, pantograph opening and the like can be caused, the train operation is influenced, and serious economic loss and social influence can be brought.
At present, the most commonly adopted measure for coping with the icing of a contact network in the prior art is thermal deicing. The thermal deicing is to apply deicing current to an overhead line system at an icing section and utilize joule heat generated by the current through the resistance of a lead of the overhead line system to melt the icing. The existing ice melting scheme needs to be carried out under the condition of power failure of a contact network, complex switching operation is needed, and the contact network can cause train shutdown after power failure, so that the trip of people is influenced, and traffic jam is caused.
Disclosure of Invention
The invention provides a multifunctional direct-current online ice melting system and method for rail transit, which can realize ice melting and ice prevention of an overhead line system under the condition of not influencing the power supply of the overhead line system and have the function of regenerative braking energy feedback of a train.
In order to achieve the purpose, the invention adopts the following technical scheme.
According to one aspect of the invention, a multifunctional rail transit direct current online ice melting system is provided, which comprises:
the direct current online deicing device is installed at a station at the middle position of a line needing deicing, the station at the middle position comprises a step-down substation, the station at the head and the tail of the line needing deicing is a traction substation, the alternating current input of the direct current online deicing device is connected with a three-phase alternating current power grid, the direct current output positive pole of the direct current online deicing device is connected at the midpoint of an uplink overhead contact system of the line needing deicing, the direct current output negative pole of the direct current online deicing device is connected at the midpoint of a downlink overhead contact system of the line needing deicing, the direct current online deicing device and the uplink and downlink overhead contact systems of the line needing deicing form a deicing path together, and direct current online deicing is realized through direct current flowing on the deicing path.
Preferably, the direct current online ice melting device comprises an AC/DC bidirectional converter, the AC/DC bidirectional converter is an adjustable direct current power supply with alternating current input and direct current output in an icing season, and the AC/DC bidirectional converter is used as an energy feeding device in a non-icing season to feed back redundant regenerative braking energy on the direct current contact network to the alternating current power grid for reuse.
Preferably, the direct current output port of the adjustable direct current power supply is connected with the ice melting channel, the adjustable direct current power supply comprises an isolation transformer and a current source type PWM converter, alternating current introduced by the adjustable direct current power supply is converted into adjustable direct current after passing through the isolation transformer and the current source type PWM converter, the current source type PWM converter works in a rectification mode, and the magnitude of output current is regulated and controlled by a current instruction in a current closed loop control mode so as to meet current control in an ice melting mode and an ice prevention mode.
Preferably, the ice melting paths include a left ice melting path and a right ice melting path, and the left ice melting path is: after the current flows out of the direct current online ice melting device, the current flows back to the direct current online ice melting device after flowing through the left part of the uplink overhead line system, the left traction substation rectifier unit bus and the left part of the downlink overhead line system; the right ice melting path is as follows: after the current flows out of the direct current online ice melting device, the current flows back to the direct current online ice melting device after flowing through the right part of the uplink overhead contact system, the right traction substation rectifier unit bus and the right part of the downlink overhead contact system.
Preferably, the left ice melting path and the right ice melting path are in parallel connection, the resistances of the left ice melting path and the right ice melting path are equal, and the currents flowing through the left ice melting path and the right ice melting path are equal.
According to another aspect of the invention, a rail transit direct current online deicing method based on the rail transit direct current online deicing system is provided, and the method comprises the following steps:
detecting the icing condition of a contact network of a line needing to be ice-melted, when the icing value of the contact network of the line needing to be ice-melted is greater than or equal to the icing warning value;
and starting an ice melting mode of the direct current online ice melting device, wherein the direct current provided by the direct current online ice melting device is an ice melting current, and the ice melting current flows through an ice melting passage to realize direct current online ice melting.
Preferably, the direct-current online ice melting device is installed at a station at the middle position of a line needing ice melting, the station at the middle position comprises a step-down substation, the first and last stations of the line needing ice melting are traction substations, the anode of the direct-current online ice melting device is connected to the midpoint of an uplink overhead contact system of the line needing ice melting, and the cathode of the direct-current online ice melting device is connected to the midpoint of a downlink overhead contact system of the line needing ice melting;
the DC current is divided into two parts after flowing out from the DC online ice melting device, wherein one part of the current IaFlowing through the left part of the ascending contact network, the busbar of the rectifier unit of the left traction substation and the left part of the descending contact network, and then flowing back to the direct-current online ice melting device to form a left ice melting loop; another part of the current IbFlowing through the right part of the ascending contact network, the rectifier unit bus of the right traction substation and the right part of the descending contact network, and then flowing back to the direct-current online ice melting device to form a right ice melting loop;
the resistance of the left ice melting loop is R1The resistance of the ice-melting loop on the right side is R2，R1＝R2
R＝(R1+R2)/2 (1)
I＝Ia+Ib＝2Ia＝2Ib (2)
Wherein R is total resistance of ice melting path, I is output current of DC online ice melting device, Ia、IbIs the ice melting current flowing through the overhead line system.
Preferably, the method further comprises:
in non-icing seasons, the direct current online ice melting device serves as an energy feedback device, the voltage value of a contact network is detected, when the voltage value of the contact network is larger than or equal to an energy feedback starting threshold value, the energy feedback function of the direct current online ice melting device is started, and the direct current online ice melting device feeds redundant regenerative braking energy on a line back to an alternating current power grid for recycling.
And when the voltage value of the contact network is smaller than the energy feedback starting threshold value, the energy feedback function of the direct current online ice melting device is closed.
Preferably, the method further comprises:
and after the direct-current online ice melting device works for a period of time, when the icing value of a contact network of the line needing ice melting is smaller than the icing warning value, the direct-current online ice melting device is switched to an anti-icing mode, the working current provided by the direct-current online ice melting device is anti-icing current, and the anti-icing current flows through an ice melting path.
Preferably, the method further comprises:
in an icing season, the direct current online ice melting device comprises an adjustable direct current power supply with alternating current input and direct current output, an alternating current input port of the adjustable direct current power supply is connected with an alternating current power grid, a direct current output port of the adjustable direct current power supply is connected with an ice melting passage, the adjustable direct current power supply comprises an isolation transformer and a current source type PWM converter, alternating current introduced by the adjustable direct current power supply is converted into adjustable direct current after passing through the isolation transformer and the current source type PWM converter, the current source type PWM converter works in a rectification mode, a current closed loop control mode is adopted, and anti-icing current or ice-melting current is regulated and controlled to be output through a current instruction according to the current control of an ice melting mode and an anti-icing mode of the direct current online ice melting device so as to meet the current control of the ice melting mode.
According to the technical scheme provided by the embodiment of the invention, the ice melting of the overhead line system is realized under the condition that the power supply of the overhead line system is not influenced, so that the influence on the train operation is avoided; the complex switching operation and the risk required by the traditional ice melting mode are avoided; the ice melting path is simple, and does not form a loop with the train and the steel rail, so that the problems of potential rise of the steel rail and current increase are avoided; an anti-icing mode is provided, icing of the contact net can be prevented, and the situation that the contact net is iced again in a short time after ice melting is avoided; has the function of recovering the regenerative braking energy of the train.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a structural diagram of a rail transit direct-current online deicing system according to an embodiment of the present invention;
fig. 2 is a structural diagram of another rail transit dc online ice melting system provided in the embodiment of the present invention;
fig. 3 is a processing flow chart of a rail transit dc online deicing method according to an embodiment of the present invention;
FIG. 4 is a flowchart illustrating a process of another rail transit DC online deicing method according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a connection manner of a controller according to an embodiment of the present invention.
Fig. 6 is a working flow of energy feedback provided by the embodiment of the present invention;
fig. 7 is another energy-feeding work flow provided by the embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
For the convenience of understanding the embodiments of the present invention, the following description will be further explained by taking several specific embodiments as examples in conjunction with the drawings, and the embodiments are not to be construed as limiting the embodiments of the present invention.
Example one
The invention provides a direct-current online ice melting system and method for rail transit, which can realize the ice prevention and ice melting of a contact network of the rail transit under the condition of not influencing the power supply of the contact network of the rail transit. Compared with the traditional ice melting mode, the method does not need power failure and switching operation of a contact network, does not influence the operation of a line train, can be used for recovering the regenerative braking energy of the train in non-icing seasons, and has wide application prospect.
The invention provides a multifunctional direct-current online ice melting system for rail transit, which is characterized in that a special direct-current online ice melting device is installed at a specific place, and the direct-current online ice melting device and an uplink and downlink overhead contact system of a line needing ice melting form an ice melting passage together, so that direct-current online ice melting is realized.
The DC online ice melting device is essentially an AC/DC bidirectional converter, and the AC/DC bidirectional converter has the functions of: in the icing season, the power supply is used as an adjustable DC power supply with AC input and DC output to provide electric energy for ice melting. In the non-icing season, the energy feedback device is used for feeding the redundant regenerative braking energy on the direct current contact network back to the alternating current power grid for recycling.
The direct-current online ice melting device is arranged at a station at the middle position of a line needing ice melting, and the station at the middle position is a step-down substation. The first and last stations of the line needing to be melted are traction substations. The alternating current input of the direct current online ice melting device is connected with a three-phase alternating current power grid, the direct current output anode of the direct current online ice melting device is connected to the midpoint of an uplink overhead contact system of the line needing ice melting, and the direct current output cathode of the direct current online ice melting device is connected to the midpoint of a downlink overhead contact system of the line needing ice melting. Here, the ascending contact network and the descending contact network are equivalent, therefore, the direct current output anode of the direct current online ice melting device can also be connected to the midpoint of the descending contact network, and the direct current output cathode is connected to the midpoint of the ascending contact network of the line needing ice melting.
The ice melting paths comprise a left ice melting path and a right ice melting path, wherein the left ice melting path is as follows: after the current flows out of the direct current online ice melting device, the current flows back to the direct current online ice melting device after flowing through the left part of the uplink overhead line system, the left traction substation rectifier unit bus and the left part of the downlink overhead line system; the ice melting path on the right side is as follows: after the current flows out of the direct current online ice melting device, the current flows back to the direct current online ice melting device after flowing through the right part of the uplink overhead contact system, the right traction substation rectifier unit bus and the right part of the downlink overhead contact system. The left ice-melting path and the right ice-melting path are in parallel connection.
The ascending contact network and the descending contact network are only marked for distinguishing, the ascending contact network and the descending contact network are completely equivalent, and the connection sequence can be changed.
The embodiment of the invention also provides a rail transit direct current online deicing method, which comprises the following steps:
M1S 1: detecting the icing condition of a contact network of a line needing ice melting, and switching a working mode according to the icing condition;
a special direct-current online ice melting device is installed at a specific place, and forms an ice melting path together with an uplink contact net and a downlink contact net of a line needing ice melting, so that direct-current online ice melting is realized.
M1S 2: and starting the direct current online ice melting device, and providing a working current by the direct current online ice melting device and forming a path.
Preferably, the direct current online ice melting method further comprises the following steps:
M1S 3: and when the direct current online ice melting device works for a period of time to ensure that the icing value of the catenary of the line needing ice melting is less than the icing warning value, closing the direct current online ice melting device.
Preferably, the working mode is as follows: when the icing value of the catenary of the line needing ice melting is greater than or equal to the icing warning value, the catenary is in an ice melting mode, and the working current provided by the direct-current online ice melting device is the ice melting current; and when the icing value of the contact net of the line needing ice melting is less than the icing warning value, the standby mode is adopted. The value of the ice-melting current can be obtained by calculation, and the specific calculation method refers to the following method embodiment.
Preferably, the operation mode further includes: according to actual needs, although the icing value of the catenary of the line needing ice melting is smaller than the icing warning value, the icing condition is judged to be about to occur according to weather factors such as current environmental temperature, wind speed conditions and the like, the catenary is in an anti-icing mode, and the working current provided by the direct-current online ice melting device is the anti-icing current. The value of the anti-icing current can be obtained by calculation, and the specific calculation method is shown in the later method embodiment.
Preferably, the step M1S2 further includes not starting the dc online deicing apparatus when the operating mode is the standby mode.
Preferably, the step M1S3 further includes, when the operating mode is the anti-icing mode, turning off the dc online de-icing apparatus when it is determined by weather factors such as current ambient temperature and wind speed conditions that icing is no longer possible.
Preferably, the invention also provides a working method of the energy feeding device in non-icing seasons, which comprises the following steps:
M2S 1: detecting a voltage value of the contact network;
M2S 2: and when the voltage value of the overhead line system is greater than or equal to the energy feedback starting threshold value, the energy feedback function is started, and redundant regenerative braking energy on the line is fed back to the alternating current power grid for recycling.
Preferably, the working method as the energy feeding device further comprises the following steps:
M2S 3: and when the energy feedback function is started for a period of time to enable the voltage value of the contact network to be smaller than the energy feedback starting threshold value, the energy feedback function is closed.
Example two
Fig. 1 is a structural diagram of a rail transit direct-current online deicing system according to an embodiment of the present invention, and as shown in fig. 1, a direct-current online deicing device (1) is installed at a station at a middle position of a line needing deicing, and the station includes a step-down substation (8), and a first and last stations of the line needing deicing should be traction substations (7). The positive pole of the direct current online ice melting device (1) is connected to the midpoint of an uplink overhead line system (2) of the line needing ice melting, and the negative pole is connected to the midpoint of a downlink overhead line system (3) of the line needing ice melting, so that an ice melting path is formed. The ice melting path is specifically as follows: the current is divided into two parts after flowing out of the direct current online ice melting device, wherein one part of the current is IaAfter flowing through the left part (21) of the ascending contact network, the rectifier unit bus (4) of the left traction substation and the left part (31) of the descending contact network, the direct current flows back to the direct current online ice melting device to form a left ice melting loop; another part of the current IbAnd the direct current flows back to the direct current online ice melting device after flowing through the right part (22) of the uplink contact network, the rectifier unit bus (5) of the right traction substation and the right part (32) of the downlink contact network to form a right ice melting loop. The direct current online ice melting device is connected to the midpoint position of a contact net of a line needing ice melting, so that the resistances of the left and right loops are equal and are R1+R2The two are in parallel relation, and the current flowing through the two are also equal, i.e. Ia＝Ib. At this time, the process of the present invention,
R＝(R1+R2)/2 (1)
I＝Ia+Ib＝2Ia＝2Ib (2)
wherein R is total resistance of ice melting path, I is output current of DC online ice melting device, Ia、IbFor melting ice current flowing through overhead lines。
With such a topology, there are several benefits: the ice melting current flowing through contact nets on the left side and the right side of the direct current online ice melting device is ensured to be equal in magnitude; the left-side loop and the right-side loop are in parallel connection, so that the total resistance of the ice melting path is reduced, the ice melting current meets the ice melting requirement, and the voltage of the access point position cannot be raised too much; the ice melting path, the train (5) and the steel rail (6) do not form a path, direct-current online ice melting can be realized, the influence on the original system is small, and the burden of the direct-current online ice melting device can not be increased when the train passes through an ice melting interval.
As shown in fig. 2, in the icing season, the dc online ice melting device is used as an adjustable dc power supply, an ac input port of the adjustable dc power supply is connected to an ac power grid, and electric energy of the adjustable dc power supply is introduced by a 35kV or 0.4kV power grid provided by a step-down substation. The direct current output port of the adjustable direct current power supply is connected with the ice melting channel, the adjustable direct current power supply comprises an isolation transformer and a current source type PWM current transformer, and alternating current introduced by the adjustable direct current power supply is converted into adjustable direct current after passing through the isolation transformer (11) and the current source type PWM current transformer (12) so as to provide energy for ice melting. At the moment, the current source type PWM converter works in a rectification mode, a current closed loop control mode is adopted, and the magnitude of output current is regulated and controlled through a current instruction so as to meet the current control of an ice melting mode and an ice prevention mode. The dc online ice melting device generally further comprises a low-voltage switch cabinet, wherein the positive electrode of the low-voltage switch cabinet is connected with the circuit breaker, and the negative electrode of the low-voltage switch cabinet is connected with the isolating switch. On one hand, protection is provided for the direct current online ice melting device, and on the other hand, the direct current online ice melting device is convenient to cut off.
In non-icing seasons, the DC online deicing device can also be used as an energy feeding device. When the voltage of the contact network rises to be larger than or equal to the energy feedback starting threshold value due to train braking, the energy feedback function is started, and redundant regenerative braking energy on the line is fed back to the alternating current power grid for recycling after passing through the current source type PWM converter and the isolation transformer. At the moment, the current source type PWM converter works in an inversion mode. As shown in fig. 3, the present embodiment provides a dc online ice melting method, which includes the following steps:
s310: and detecting the icing condition of the contact network of the line needing to melt ice, and switching the working mode according to the icing condition. The working modes comprise an ice melting mode, an ice prevention mode and a standby mode: when the icing value of a contact net of a line needing ice melting is greater than or equal to the icing warning value, the line is in an ice melting mode, and the working current provided by the direct-current online ice melting device is the ice melting current I1(ii) a And when the icing value of the contact net of the line needing to melt ice is less than the icing warning value, the standby mode is adopted. According to actual needs, the working mode can further comprise: although the icing value of the contact net of the line needing ice melting is less than the icing warning value, the current environmental temperature, wind speed condition and other weather factors judge that the icing condition is about to occur, the mode is an anti-icing mode, and the working current provided by the direct-current online ice melting device is anti-icing current I2。
The method for acquiring the ice melting value of the ice melting line can be implemented by manually observing or installing a monitoring camera on the ice melting line to shoot pictures, and identifying the ice coating value by combining an intelligent algorithm.
S320: when the working mode is the standby mode, the direct-current online ice melting device is not started; when the working mode is the ice melting mode, the direct current online ice melting device is started, and the current source type PWM rectifier receives an ice melting current instruction I ═ I1Providing ice melting current and forming a path; when the working mode is the anti-icing mode, the direct current online ice melting device is started, and the current source type PWM rectifier receives an anti-icing current instruction I ═ I2And providing an anti-icing current and forming a path.
As shown in fig. 4, the method for melting ice on line by direct current further includes the steps of:
s330: working in an ice melting mode, when the direct-current online ice melting device works for a period of time to ensure that the icing value of a contact network of a line needing ice melting is less than the icing warning value, closing the direct-current online ice melting device; and working in an anti-icing mode, and turning off the direct-current online ice melting device when judging that the possibility of ice coating is not generated any more according to weather factors such as current environment temperature, wind speed conditions and the like.
The working modes of the online ice melting device can be switched manually, and the controller can also control the switching according to the ice coating value. The controller can be embedded in the direct current online ice melting device. Fig. 5 shows a connection mode of a controller according to an embodiment of the present invention.
Ice melting current I provided by DC online ice melting device1And anti-icing current I2The value of (a) is related to weather factors such as ambient temperature and wind speed conditions, and needs to be obtained through calculation. Wherein the ice melting current I1The calculation formula of (a) is as follows:
for the soft ice:
for rime:
I1-the ice-melting current in units of: a;
R0-the resistance of the wire per unit length at an air temperature of 0 ℃ in units of: omega/m;
Tr-ice melting time in units of: h;
Δ t-the difference between the conductor temperature and the ambient air temperature, in units of: DEG C;
RTO-equivalent ice layer thermal conduction resistance, unit is: c cm/W;
RT1-convection and radiation equivalent thermal resistance, in units: c cm/W;
go-the density of the ice in units of: g/cm3；
b-ice layer thickness, namely ice thickness of each edge of the ice coating, and the unit is as follows: cm;
d-wire diameter, unit: cm;
d is the outer diameter of the conductor after being coated with ice, and the unit is: cm;
v-wind speed, in units: m/s;
λ -thermal conductivity, in units: w/cm. DEG C
Anti-icing current I2The calculation formula of (a) is as follows:
(I2/2)2R0＝[0.143εid+0.82(vd)0.75](t1-t2) (4)
wherein epsiloniIs the emissivity coefficient; t is t1The temperature for ensuring that the wire does not ice; t is t2The ambient temperature at which ice forms.
In consideration of convenience of engineering application, a table is generally used for listing the ice melting current and the ice preventing current under various working conditions so as to facilitate quick query.
After the direct-current online ice melting device finishes ice melting on the contact network, the contact network can be iced again due to severe weather factors, and the situation that the contact network is repeatedly iced can be effectively avoided by starting the ice prevention mode of the direct-current online ice melting device.
As shown in fig. 6, the present embodiment further provides a working method as an energy feeding device in non-icing seasons, comprising the following steps:
s610: detecting the voltage value of a contact net on an installation line section of the direct-current online ice melting device;
s620: when the detected voltage value of the contact network is smaller than the energy feedback starting threshold value, the energy feedback function of the direct current online ice melting device is not started; and when the detected voltage value of the overhead line system is greater than or equal to the energy feedback starting threshold value, starting the energy feedback function of the direct current online ice melting device, and feeding the redundant regenerative braking energy on the line back to the alternating current power grid for recycling.
As shown in fig. 7, the working method as the energy feeding device further includes:
s630: and after the energy feedback function of the direct current online ice melting device is started for a period of time, when the voltage value of the overhead line system is smaller than the energy feedback starting threshold value, the energy feedback function of the direct current online ice melting device is closed.
In non-icing seasons, when a plurality of trains run on the line and the energy generated by train braking is greater than the traction energy of other trains, the direct current online ice melting device can also be used as an energy feedback device, and the redundant regenerative braking energy on the line is fed back to the alternating current power grid for recycling, so that a good energy-saving effect is achieved.
In conclusion, the ice melting of the overhead line system is realized under the condition that the power supply of the overhead line system is not influenced, and the influence on the train operation is avoided; the complex switching operation and the risk required by the traditional ice melting mode are avoided; the ice melting path is simple, and does not form a loop with the train and the steel rail, so that the problems of potential rise of the steel rail and current increase are avoided; the anti-icing mode is provided, icing of the contact net can be prevented, and the situation that the contact net is iced again in a short time after ice melting is avoided.
The system and the method provided by the embodiment of the invention have the function of recovering the regenerative braking energy of the train.
Those of ordinary skill in the art will understand that: the figures are merely schematic representations of one embodiment, and the blocks or flow diagrams in the figures are not necessarily required to practice the present invention.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for apparatus or system embodiments, since they are substantially similar to method embodiments, they are described in relative terms, as long as they are described in partial descriptions of method embodiments. The above-described embodiments of the apparatus and system are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A multifunctional rail transit direct current online deicing system is characterized by comprising:
the direct current online deicing device is installed at a station at the middle position of a line needing deicing, the station at the middle position comprises a step-down substation, the station at the head and the tail of the line needing deicing is a traction substation, the alternating current input of the direct current online deicing device is connected with a three-phase alternating current power grid, the direct current output positive pole of the direct current online deicing device is connected at the midpoint of an uplink overhead contact system of the line needing deicing, the direct current output negative pole of the direct current online deicing device is connected at the midpoint of a downlink overhead contact system of the line needing deicing, the direct current online deicing device and the uplink and downlink overhead contact systems of the line needing deicing form a deicing path together, and direct current online deicing is realized through direct current flowing on the deicing path.
2. The system of claim 1, wherein the DC online deicing apparatus comprises an AC/DC bidirectional converter, the AC/DC bidirectional converter is an adjustable DC power supply with AC input and DC output during icing season, and the AC/DC bidirectional converter is used as an energy feeding apparatus to feed back excess regenerative braking energy on the DC contact network to the AC power grid for reuse during non-icing season.
3. The system of claim 2, wherein an ac input port of the adjustable dc power supply is connected to an ac power grid, a dc output port of the adjustable dc power supply is connected to the ice melting path, the adjustable dc power supply comprises an isolation transformer and a current source PWM converter, an ac current introduced by the adjustable dc power supply is converted into an adjustable dc current after passing through the isolation transformer and the current source PWM converter, and the current source PWM converter operates in a rectification mode, and regulates the magnitude of the output current through a current instruction in a current closed loop control manner to satisfy current control in the ice melting mode and the ice prevention mode.
4. The system of claim 1, wherein the ice-melt paths comprise a left ice-melt path and a right ice-melt path, and wherein the left ice-melt path is: after the current flows out of the direct current online ice melting device, the current flows back to the direct current online ice melting device after flowing through the left part of the uplink overhead line system, the left traction substation rectifier unit bus and the left part of the downlink overhead line system; the right ice melting path is as follows: after the current flows out of the direct current online ice melting device, the current flows back to the direct current online ice melting device after flowing through the right part of the uplink overhead contact system, the right traction substation rectifier unit bus and the right part of the downlink overhead contact system.
5. The system of claim 4, wherein the left ice-melting path and the right ice-melting path are in parallel, wherein the resistances of the left ice-melting path and the right ice-melting path are equal, and the currents flowing through the left ice-melting path and the right ice-melting path are equal.
6. A rail transit direct current online deicing method based on the multifunctional rail transit direct current online deicing system of any one of claims 1 to 5, characterized by comprising:
detecting the icing condition of a contact network of a line needing to be ice-melted, when the icing value of the contact network of the line needing to be ice-melted is greater than or equal to the icing warning value;
and starting an ice melting mode of the direct current online ice melting device, wherein the direct current provided by the direct current online ice melting device is an ice melting current, and the ice melting current flows through an ice melting passage to realize direct current online ice melting.
7. The method according to claim 6, wherein the direct current online ice melting device is installed at a station at the middle position of the line needing ice melting, the station at the middle position comprises a step-down substation, the first and last stations of the line needing ice melting are traction substations, the positive electrode of the direct current online ice melting device is connected to the midpoint position of an uplink catenary of the line needing ice melting, and the negative electrode of the direct current online ice melting device is connected to the midpoint position of a downlink catenary of the line needing ice melting;
the DC current is divided into two parts after flowing out from the DC online ice melting device, wherein one part of the current IaFlowing through the left part of the ascending contact network, the busbar of the rectifier unit of the left traction substation and the left part of the descending contact network, and then flowing back to the direct-current online ice melting device to form a left ice melting loop; another part of the current IbFlowing through the right part of the ascending contact network, the rectifier unit bus of the right traction substation and the right part of the descending contact network, and then flowing back to the direct-current online ice melting device to form a right ice melting loop;
the resistance of the left ice melting loop is R1The resistance of the ice-melting loop on the right side is R2，R1＝R2
R＝(R1+R2)/2 (1)
I＝Ia+Ib＝2Ia＝2Ib (2)
Wherein R is total resistance of ice melting path, I is output current of DC online ice melting device, Ia、IbIs the ice melting current flowing through the overhead line system.
8. The method of claim 7, further comprising:
in non-icing seasons, the direct current online ice melting device serves as an energy feedback device, the voltage value of a contact network is detected, when the voltage value of the contact network is larger than or equal to an energy feedback starting threshold value, the energy feedback function of the direct current online ice melting device is started, and the direct current online ice melting device feeds redundant regenerative braking energy on a line back to an alternating current power grid for recycling.
And when the voltage value of the contact network is smaller than the energy feedback starting threshold value, the energy feedback function of the direct current online ice melting device is closed.
9. The method of claim 6, further comprising:
and after the direct-current online ice melting device works for a period of time, when the icing value of a contact network of the line needing ice melting is smaller than the icing warning value, the direct-current online ice melting device is switched to an anti-icing mode, the working current provided by the direct-current online ice melting device is anti-icing current, and the anti-icing current flows through an ice melting path.
10. The method of claim 7, further comprising:
in an icing season, the direct current online ice melting device comprises an adjustable direct current power supply with alternating current input and direct current output, an alternating current input port of the adjustable direct current power supply is connected with an alternating current power grid, a direct current output port of the adjustable direct current power supply is connected with an ice melting passage, the adjustable direct current power supply comprises an isolation transformer and a current source type PWM (pulse width modulation) converter, alternating current introduced by the adjustable direct current power supply is converted into adjustable direct current after passing through the isolation transformer and the current source type PWM converter, the current source type PWM converter works in a rectification mode, a current closed loop control mode is adopted, and according to current control of an ice melting mode and an ice preventing mode of the direct current online ice melting device, the ice preventing current or the ice melting current is regulated and controlled to be output.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113007728A (en) * | 2021-03-11 | 2021-06-22 | 机械工业第九设计研究院有限公司 | Anti-freezing control scheme for RTO inlet valve in severe cold area |
| CN114161999A (en) * | 2021-11-18 | 2022-03-11 | 新风光电子科技股份有限公司 | Control method of bidirectional converter device with subway traction network ice melting function |
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| CN113007728A (en) * | 2021-03-11 | 2021-06-22 | 机械工业第九设计研究院有限公司 | Anti-freezing control scheme for RTO inlet valve in severe cold area |
| CN113007728B (en) * | 2021-03-11 | 2023-03-31 | 机械工业第九设计研究院股份有限公司 | Anti-freezing control scheme for RTO inlet valve in severe cold area |
| CN114161999A (en) * | 2021-11-18 | 2022-03-11 | 新风光电子科技股份有限公司 | Control method of bidirectional converter device with subway traction network ice melting function |
| CN114825237A (en) * | 2022-05-17 | 2022-07-29 | 深圳量云能源网络科技有限公司 | Contact net anti-icing and ice-melting control method and system based on rail transit system |
| CN114825237B (en) * | 2022-05-17 | 2024-01-16 | 深圳量云能源网络科技有限公司 | Overhead line anti-icing and ice-melting control method and system based on rail transit system |
| CN114937968A (en) * | 2022-05-19 | 2022-08-23 | 西南交通大学 | Direct-current ice melting device for electrified railway contact network and control method thereof |
| CN115642552A (en) * | 2022-10-10 | 2023-01-24 | 中铁第一勘察设计院集团有限公司 | Direct-current online anti-ice melting system of urban rail transit overhead line system |
| CN115642552B (en) * | 2022-10-10 | 2024-04-30 | 中铁第一勘察设计院集团有限公司 | Urban rail transit contact net direct current online anti-ice-melting system |
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