CN112260199A - Online ice melting system and method for rail transit alternating current - Google Patents
Online ice melting system and method for rail transit alternating current Download PDFInfo
- Publication number
- CN112260199A CN112260199A CN202011039054.0A CN202011039054A CN112260199A CN 112260199 A CN112260199 A CN 112260199A CN 202011039054 A CN202011039054 A CN 202011039054A CN 112260199 A CN112260199 A CN 112260199A
- Authority
- CN
- China
- Prior art keywords
- ice melting
- ice
- alternating current
- online
- melting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- 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
-
- 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
Abstract
The invention provides a rail transit alternating current online ice melting system and method. The system comprises an alternating current online ice melting device, wherein the alternating current online ice melting device is arranged at a station at the middle position of a line needing ice melting, the station at the middle position comprises a voltage reduction substation, the head and tail stations of the line needing ice melting are traction substations, the alternating current input of the alternating current online ice melting device is connected with a three-phase alternating current power grid, one end of the output of the alternating current online ice melting device is connected to the middle point of an uplink overhead contact system of the line needing ice melting, the other end of the output of the alternating current online ice melting device is connected to the middle point of a downlink overhead contact system of the line needing ice. When ice needs to be melted, the voltage provided by the alternating current online ice melting device is the ice melting voltage and forms a path, and the ice melting current flows through the ice melting path, so that the alternating current online ice melting is realized. According to 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, and the complex switching operation required by the traditional ice melting method is avoided; can prevent the contact net from icing.
Description
Technical Field
The invention relates to the technical field of rail transit safety control, in particular to a rail transit alternating 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 an alternating current online ice melting system and method for rail transit, which realize the ice melting and ice preventing functions of a contact network under the condition of not influencing the power supply of the contact network.
In order to achieve the purpose, the invention adopts the following technical scheme.
According to one aspect of the invention, an online rail transit alternating-current ice melting system is provided, which comprises:
the alternating current online ice melting device is arranged at a station at the middle position of a line needing ice melting, the station at the middle position comprises a voltage reduction substation, the head and tail stations of the line needing ice melting are traction substations, the alternating current input of the alternating current online ice melting device is connected with a three-phase alternating current power grid, one end of the output of the alternating current online ice melting device is connected to the midpoint of an uplink overhead contact system of the line needing ice melting, the other end of the output of the alternating current online ice melting device is connected to the midpoint of a downlink overhead contact system of the line needing ice melting, the alternating current online ice melting device and the uplink and downlink overhead contact systems of the line needing ice melting form an ice melting path together, and alternating current online ice melting.
Preferably, the alternating current online ice melting device comprises an isolation transformer, an AC/DC converter and a DC/AC converter which are sequentially connected in series, an alternating current input port of the isolation transformer is connected with an alternating current power grid, an alternating current output port of the isolation transformer is connected with the AC/DC converter and the DC/AC converter, three-phase alternating current input from the outside is converted into direct current by the front-stage AC/DC converter after passing through the isolation transformer, and then the direct current is inverted into single-phase alternating current with voltage and frequency meeting ice melting requirements by the rear-stage DC/AC converter.
Preferably, the alternating current online ice melting device 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.
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 alternating current online ice melting device, the current flows 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 and then flows back to the alternating current online ice melting device; the right ice melting path is as follows: after the current flows out of the alternating current online ice melting device, the current flows back to the alternating 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 alternating current online deicing method based on the rail transit alternating current online deicing system is provided, and 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 alternating current online ice melting device, wherein the voltage provided by the alternating current online ice melting device is an ice melting voltage and forms a path, the current required by the catenary for melting ice is an ice melting current, and the ice melting current flows through the ice melting path to realize alternating current online ice melting.
Preferably, the alternating 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, one end of the output of the alternating current online ice melting device is connected to the midpoint position of an uplink overhead contact system of the line needing ice melting, and the other end of the output of the alternating current online ice melting device is connected to the midpoint position of a downlink overhead contact system of the line needing ice melting;
the alternating current is divided into two parts after flowing out of the alternating current 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 alternating 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 busbar of the rectifier unit of the right traction substation and the right part of the descending contact network, and then flowing back to the alternating 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 channel, I is output current of AC online ice melting device, Ia、IbIs the ice melting current flowing through the overhead line system.
Preferably, the method further comprises:
detecting the icing condition of a contact network of a line needing ice melting, and setting the working modes of the alternating-current online ice melting device to comprise an ice melting mode and an anti-icing mode;
the method comprises the steps of detecting the icing condition of a contact network of the line needing to melt ice, and setting working voltage according to the icing condition, wherein the working voltage comprises the following steps: 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 alternating-current online ice melting device works in an ice melting mode, and the provided voltage is ice melting voltage V1And forming a passage, wherein the current flowing through the ice melting passage is ice melting current I1；
When the AC online ice melting device works for a period of time and the icing value of the catenary of the line needing ice melting is less than the icing warning value, the AC online ice melting device is switched to an anti-icing mode, and the voltage provided by the AC online ice melting device is anti-icing voltage V2And forming a path, the current flowing through the ice melting path is the anti-icing current I2；
The calculation formula of the working voltage of the alternating-current online ice melting device is as follows:
V1＝I1×R (3)
V2＝I2×R (4)
preferably, the method further comprises:
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. degree.C.
Preferably, the method further comprises:
anti-icing current I2The calculation formula of (a) is as follows:
(I2/2)2R0＝[0.143εid+0.82(vd)0.75](t1-t2) (6)
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 the formula, V1V2I1I2All are effective values.
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 an online rail transit ac ice melting system according to an embodiment of the present invention;
FIG. 2 is a structural diagram of another rail transit alternating-current online deicing system provided in the embodiment of the present invention;
FIG. 3 is a structural diagram of an AC online ice melting device according to an embodiment of the present invention;
FIG. 4 is a processing flow chart of an alternating current online ice melting method according to an embodiment of the present invention;
FIG. 5 is a flowchart illustrating a process of another method for online AC ice melting according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a connection manner of a controller according to an 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 an online alternating-current 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 power failure switching operation of a contact network is not needed, and the operation of a line train is not influenced. The method utilizes the skin effect of the high-frequency alternating current power supply to increase the line impedance and reduce the ice melting current value.
The invention provides a multifunctional alternating current online ice melting system for rail transit, which is characterized in that a special alternating current online ice melting device is arranged at a specific place, and the alternating current online ice melting device and an uplink and downlink contact network of a line needing ice melting form an ice melting passage together, so that alternating current online ice melting is realized.
The AC online ice melting device is essentially a special high-frequency AC power supply converter, and the high-frequency AC power supply converter has the functions of: and converting the alternating current input by the three-phase alternating current network into single-phase high-frequency alternating current meeting the ice melting requirement. The topology of the high frequency ac power converter may include: AC-DC and DC-AC two-stage converters.
The alternating 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. And the alternating current input of the alternating current online ice melting device is connected with a three-phase alternating current power grid, one end of the output of the alternating current online ice melting device is connected to the midpoint of the uplink overhead contact system of the line needing ice melting, and the other end of the output of the alternating current online ice melting device is connected to the midpoint of the downlink overhead contact system 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 alternating current online ice melting device, the current flows 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 and then flows back to the alternating current online ice melting device; the ice melting path on the right side is as follows: after the current flows out of the alternating current online ice melting device, the current flows back to the alternating 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 skin effect is also called as skin effect, and means that when alternating current passes through a conductor, the current is concentrated on the surface of the conductor and flows, but is not evenly distributed in the cross section of the whole conductor, which is equivalent to reducing the cross section of current transmission and increasing the transmission resistance of a line.
Example two
Fig. 1 is a structural diagram of an ac online deicing system for rail transit according to an embodiment of the present invention, and as shown in fig. 1, an ac 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 the first and last stations of the line needing deicing should be traction substations (7). This is to avoid the short circuit of the ice melting device caused by the formation of a path by the uplink and downlink overhead contact system at the station at the middle position.
The alternating current online alternating current ice melting device (1) provides high-frequency alternating current which is loaded into an ice melting channel to generate a skin effect, so that electric heating ice melting is realized. One end of the output of the AC online AC ice melting device (1) is connected with the midpoint of an uplink overhead line system (2) of the line needing ice melting, and the other end is connected with a downlink contact of the line needing ice meltingAnd the middle point position of the net (3) forms an ice melting passage. The ice melting path is specifically as follows: the current is divided into two parts after flowing out of the alternating 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 current flows back to the alternating current online ice melting device to form a left ice melting loop; another part of the current IbAnd the ice flows back to the alternating 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. Because the alternating current online ice melting device is connected at the midpoint of a contact net of a line needing ice melting, 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 channel, I is output current of AC online ice melting device, Ia、IbIs the ice melting current flowing through the overhead line system.
With such ice melting systems and methods, there are several benefits: the left and right loops of the ice melting passage are in parallel connection, so that the ice melting currents flowing through contact nets on the left and right sides of the ice melting device are equal; the total resistance of the ice melting path is reduced, so that the amplitude of the introduced alternating-current ice melting voltage is not too large while the ice melting current meets the ice melting requirement; the method adopts an alternating-current ice melting mode, namely, an alternating-current ice melting voltage component is added to the direct-current voltage of the contact network, the average value of the direct-current voltage of the contact network is not changed, the caused direct-current network voltage fluctuation can be also considered by a train traction system, and the train operation cannot be influenced; based on the skin effect, the effective value of the ice melting current is smaller than that of the ice melting current required by direct current ice melting.
The alternating-current online ice melting device is designed with an anti-icing mode, and the situation that the contact net is covered with ice again in a short time after ice melting due to severe weather factors can be effectively avoided.
Fig. 2 is a structural diagram of another rail transit AC online ice melting system according to an embodiment of the present invention, and as shown in fig. 2, the AC online ice melting device, as a dedicated ice melting power source, mainly includes an isolation transformer (11), an AC/DC converter (12), and a DC/AC converter (13) connected in series in sequence. The three-phase alternating current input to the alternating current online ice melting device is introduced by a 35kV or 0.4kV power grid of a step-down substation, the input three-phase alternating current passes through an isolation transformer and is converted into direct current by a front-stage AC/DC converter, and then the direct current is inverted into single-phase alternating current with voltage and frequency meeting ice melting requirements by a rear-stage DC/AC converter so as to provide energy for ice melting. Fig. 3 is a structural diagram of an ac online ice melting device according to an embodiment of the present invention, and as shown in fig. 3, the ac online ice melting device includes a low-voltage switch cabinet, a positive electrode serving as a circuit breaker, and a negative electrode disconnecting switch (14), which on one hand provides protection for the ice melting device and on the other hand facilitates cutting off the ice melting device.
Fig. 4 is a processing flow chart of an alternating current online ice melting method provided by the embodiment of the invention, and the method includes the following steps:
s410: the working modes of the alternating current online ice melting device comprise an ice melting mode and an anti-icing mode.
And detecting the icing condition of the contact net of the line needing to melt ice, and setting working voltage according to the icing condition. The working voltage comprises: when the icing value of a contact network of a line needing ice melting is greater than or equal to the icing warning value, the alternating-current online ice melting device works in an ice melting mode, and the provided voltage is ice melting voltage V1And a path is formed, and the current required by the ice melting of the contact net is the ice melting current I1(ii) a When the icing value of the contact net of the line needing ice melting is smaller than the icing warning value, but the icing condition is judged to occur according to weather factors such as the current environmental temperature, the wind speed condition and the like, the current required by the contact net for ice prevention is the anti-icing current I2At the moment, the alternating current online ice melting device works in an anti-icing mode, and the provided voltage is anti-icing voltage V2。
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.
S420: when working in the ice melting mode, the AC online ice melting device is started to operate and provides ice melting voltage V1And forming a passage, wherein the current flowing through the ice melting passage is ice melting current I1(ii) a When the device works in the anti-icing mode, the alternating current online ice melting device is operated and started, and the alternating current online ice melting device provides anti-icing voltage V2And forming a path, the current flowing through the ice melting path is the anti-icing current I2。
As shown in fig. 5, the online ice melting method further includes the steps of:
s430: in the ice-melting mode, after the alternating current online ice-melting device works for a period of time, when the icing value of a contact network of a line needing ice melting is less than the icing warning value, the alternating current online ice-melting device is switched to the anti-icing mode, and the voltage provided by the alternating current online ice-melting device is the anti-icing voltage V2And forming a path, wherein the current required by the contact network for deicing is the anti-icing current, and the anti-icing current flows through the deicing path. And in the anti-icing mode, when the possibility of icing is judged to be no longer present according to weather factors such as the current environment temperature, the wind speed condition and the like, the ice melting device is closed.
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. Fig. 6 is a schematic diagram of a connection manner of a controller according to an embodiment of the present invention, where the controller may be embedded in an ac online ice melting device.
The calculation formula of the working voltage of the alternating-current online ice melting device is as follows:
V1＝I1×R (3)
V2＝I2×R (4)
ice melting current I1And anti-icing current I2The value of (b) is related to weather factors such as ambient temperature and wind speed conditions, and can 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. degree.C.
Anti-icing current I2The calculation formula of (a) is as follows:
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 the formula, V1 V2 I1 I2All are effective values.
With such ice melting systems and methods, there are several benefits: the left and right loops of the ice melting passage are in parallel connection, so that the ice melting currents flowing through contact nets on the left and right sides of the ice melting device are equal; the total resistance of the ice melting path is reduced, so that the amplitude of the introduced alternating-current ice melting voltage is not too large while the ice melting current meets the ice melting requirement; the method adopts an alternating-current ice melting mode, namely, an alternating-current ice melting voltage component is added to the direct-current voltage of the contact network, the average value of the direct-current voltage of the contact network is not changed, the caused direct-current network voltage fluctuation can be also considered by a train traction system, and the train operation cannot be influenced; based on the skin effect, the ice melting current required is smaller compared to direct current ice melting.
After the alternating current online ice melting device finishes ice melting on the contact network, the contact network can be coated with ice again due to severe weather factors, and the ice preventing mode of the alternating current online ice melting device is started at the moment, so that the situation that the contact network is repeatedly coated with ice can be effectively avoided.
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 method adopts an alternating-current ice melting mode, the average voltage value of the contact network is unchanged, and the influence of the ice melting voltage on the contact network is avoided; based on the skin effect, the size of the ice melting current is reduced; the power failure is not needed in the ice melting process of the overhead contact system, 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 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 special ice melting device is arranged at the section of the line needing ice melting, high-frequency ice melting current is transmitted to the overhead contact system through the ice melting channel, thermal ice melting and ice prevention are realized by utilizing the skin effect, the complex switching operation required by the traditional ice melting method is avoided, the normal power supply of the overhead contact system and the operation of a line train are not influenced, the structure is simple, and the realization is easy. In addition, compared with a direct-current ice melting scheme, the high-frequency alternating-current ice melting is adopted, the ice melting current is small, the average value of the voltage of a contact network cannot be changed, high-frequency harmonic waves can be easily filtered by a vehicle-mounted filter, and the train operation cannot be influenced.
The left and right loops of the ice melting passage are in parallel connection, so that the ice melting currents flowing through contact nets on the left and right sides of the ice melting device are equal; the total resistance of the ice melting path is reduced, so that the amplitude of the introduced alternating-current ice melting voltage is not too large while the ice melting current meets the ice melting requirement; the method adopts an alternating-current ice melting mode, namely, an alternating-current ice melting voltage component is added to the direct-current voltage of the contact network, the average value of the direct-current voltage of the contact network is not changed, the caused direct-current network voltage fluctuation can be also considered by a train traction system, and the train operation cannot be influenced; based on the skin effect, the ice melting current required is smaller compared to direct current ice melting.
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. The rail transit alternating current online ice melting system is characterized by comprising:
the alternating current online ice melting device is arranged at a station at the middle position of a line needing ice melting, the station at the middle position comprises a voltage reduction substation, the head and tail stations of the line needing ice melting are traction substations, the alternating current input of the alternating current online ice melting device is connected with a three-phase alternating current power grid, one end of the output of the alternating current online ice melting device is connected to the midpoint of an uplink overhead contact system of the line needing ice melting, the other end of the output of the alternating current online ice melting device is connected to the midpoint of a downlink overhead contact system of the line needing ice melting, the alternating current online ice melting device and the uplink and downlink overhead contact systems of the line needing ice melting form an ice melting path together, and alternating current online ice melting.
2. The system according to claim 1, wherein the AC online deicing device comprises an isolation transformer, an AC/DC converter and a DC/AC converter which are connected in series in sequence, an AC input port of the isolation transformer is connected to an AC power grid, an AC output port of the isolation transformer is connected to the AC/DC converter and the DC/AC converter, an externally input three-phase AC power is converted into a DC power by the front-stage AC/DC converter after passing through the isolation transformer, and the DC power is then inverted into a single-phase AC power having a voltage and a frequency meeting deicing requirements by the rear-stage DC/AC converter.
3. The system of claim 2, wherein the ac online deicing apparatus further comprises a low-voltage switch cabinet, wherein a positive electrode of the low-voltage switch cabinet is connected to the circuit breaker, and a negative electrode of the low-voltage switch cabinet is connected to the disconnecting switch.
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 alternating current online ice melting device, the current flows 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 and then flows back to the alternating current online ice melting device; the right ice melting path is as follows: after the current flows out of the alternating current online ice melting device, the current flows back to the alternating 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. The rail transit alternating current online deicing method based on the rail transit alternating current online deicing system as claimed in any one of claims 1 to 5, characterized by comprising 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 alternating current online ice melting device, wherein the voltage provided by the alternating current online ice melting device is an ice melting voltage and forms a path, the current required by the catenary for melting ice is an ice melting current, and the ice melting current flows through the ice melting path to realize alternating current online ice melting.
7. The method according to claim 6, wherein the AC online deicing device is installed at a station at the middle position of the line needing deicing, the station at the middle position comprises a step-down substation, the first and last stations of the line needing deicing are traction substations, one end of the output of the AC online deicing device is connected to the midpoint position of an uplink catenary of the line needing deicing, and the other end of the output of the AC online deicing device is connected to the midpoint position of a downlink catenary of the line needing deicing;
the alternating current is divided into two parts after flowing out of the alternating current 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 alternating 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 busbar of the rectifier unit of the right traction substation and the right part of the descending contact network, and then flowing back to the alternating 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 channel, I is output current of AC online ice melting device, Ia、IbIs the ice melting current flowing through the overhead line system.
8. The method of claim 7, further comprising:
detecting the icing condition of a contact network of a line needing ice melting, and setting the working modes of the alternating-current online ice melting device to comprise an ice melting mode and an anti-icing mode;
the method comprises the steps of detecting the icing condition of a contact network of the line needing to melt ice, and setting working voltage according to the icing condition, wherein the working voltage comprises the following steps: 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 alternating-current online ice melting device works in an ice melting mode, and the provided voltage is ice melting voltage V1And forming a passage, wherein the current flowing through the ice melting passage is ice melting current I1；
When the communication is atAfter the line ice melting device works for a period of time, when the icing value of the overhead contact system of the line needing ice melting is less than the icing warning value, the alternating current online ice melting device is switched to an anti-icing mode, and the voltage provided by the alternating current online ice melting device is anti-icing voltage V2And forming a path, the current flowing through the ice melting path is the anti-icing current I2；
The calculation formula of the working voltage of the alternating-current online ice melting device is as follows:
V1＝I1×R (3)
V2＝I2×R (4)
9. the method of claim 8, further comprising:
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. degree.C.
10. The method of claim 7, further comprising:
anti-icing current I2The calculation formula of (a) is as follows:
(I2/2)2R0＝[0.143εid+0.82(vd)0.75](t1-t2) (6)
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.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011039054.0A CN112260199A (en) | 2020-09-28 | 2020-09-28 | Online ice melting system and method for rail transit alternating current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011039054.0A CN112260199A (en) | 2020-09-28 | 2020-09-28 | Online ice melting system and method for rail transit alternating current |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112260199A true CN112260199A (en) | 2021-01-22 |
Family
ID=74233357
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011039054.0A Pending CN112260199A (en) | 2020-09-28 | 2020-09-28 | Online ice melting system and method for rail transit alternating current |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112260199A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113370849A (en) * | 2021-07-30 | 2021-09-10 | 清华大学 | Traction power supply system with ice melting and energy feedback functions |
| 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 |
| 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 |
-
2020
- 2020-09-28 CN CN202011039054.0A patent/CN112260199A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113370849A (en) * | 2021-07-30 | 2021-09-10 | 清华大学 | Traction power supply system with ice melting and energy feedback functions |
| 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 |
| 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 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112260199A (en) | Online ice melting system and method for rail transit alternating current | |
| CN112260198A (en) | Multifunctional rail transit direct-current online ice melting system and method | |
| EP3406476B1 (en) | Locomotive regenerative electric energy feedback system with ice melting function and control method | |
| CN101242087A (en) | Ice fusion method for power transmission line | |
| CN107215246B (en) | Intelligent ice melting system of contact network | |
| CN102638019B (en) | Direct-current catenary de-icing method of high-speed electrified railway | |
| CN201446892U (en) | DC Thawing System of Electrified Railway Catenary Systems | |
| WO2021136286A1 (en) | System and method for melting ice on overhead line by using photovoltaic power generation | |
| CN108899853B (en) | Live-line ice melting topological system and ice melting method thereof | |
| CN102623941A (en) | Direct current deicing device for 10KV rural power grid distribution line | |
| CN213879227U (en) | Multifunctional direct-current online ice melting system for rail transit | |
| CN213879226U (en) | Rail transit alternating-current online ice melting system | |
| CN103247991B (en) | A kind of contact nets in electrified railways utilize phase fault to realize anti-icing de-icing method | |
| CN112102984A (en) | Novel steel core ice melting insulated wire and ice melting system and method thereof | |
| CN203689973U (en) | High-resistance steel core ice-melting lead | |
| CN107215245B (en) | Energy self-circulation contact net ice melting system | |
| CN103730201A (en) | High-resistance steel core ice melting wire | |
| CN103151745A (en) | Method for deicing by connecting double-side deicing overhead ground wires in series | |
| CN206650402U (en) | The deicing device of wire suspension string | |
| CN208362848U (en) | A kind of highway ice-melt snow-melting system based on Mobile energy storage device | |
| CN102931621B (en) | Alternating-current ice melting device for distribution line | |
| CN202243058U (en) | Anti-icing and ice-melting system applicable to high-speed rails | |
| KR20210057261A (en) | Anti-frost heating system in Rubber-tire AGT | |
| CN201230189Y (en) | Ice and snow preventing apparatus for electricity transmission line | |
| CN101465532A (en) | Circuit for DC sleet melting AC line |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |