CN112054466A - De-service lithium battery-based ice melting device and method - Google Patents
De-service lithium battery-based ice melting device and method Download PDFInfo
- Publication number
- CN112054466A CN112054466A CN202010891754.6A CN202010891754A CN112054466A CN 112054466 A CN112054466 A CN 112054466A CN 202010891754 A CN202010891754 A CN 202010891754A CN 112054466 A CN112054466 A CN 112054466A
- Authority
- CN
- China
- Prior art keywords
- ice
- ice melting
- lithium battery
- current
- temperature
- 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
Abstract
The invention discloses an ice melting device and method based on a retired lithium battery. The invention uses the retired lithium battery for the secondary ice melting work of the high-voltage transmission line, not only can finish the ice melting work within the specified time, but also can greatly save the ice melting cost.
Description
Technical Field
The invention relates to an ice melting device and method based on a retired lithium battery, and belongs to the technical field of overhead line maintenance of power grids.
Background
In recent years, the rapid development of industrial activities aggravates extreme climate change, in early 2008, the southern area of China suffers from serious ice and snow disasters, and the ice coating fault of the power transmission line has serious influence on disaster relief work and life of people. The ice coating of the power transmission line is easily caused by extremely low temperature and high air humidity at night in northeast regions in winter and spring and mountain forest regions in south China. In a low-temperature environment in winter, the weight and sag of a power transmission line are increased after the wires of a power grid are coated with ice, and accidents such as wire breakage, tower falling, overhead line galloping and the like can be caused; after the insulator of the wire is coated with ice, the insulation strength is reduced, so that flashover accidents are easily caused; if the ice is not melted by the ice melting device in time, the outer layer of the overhead line is easily abraded, the steel core is easily moved and the like due to the falling and sliding of the ice layer when the environmental temperature is increased. With the construction of electrified railways and the high-speed development of ultra-high and extra-high voltage long-distance power transmission in China, if a power grid fault is caused by ice coating of a modern power grid, the power grid is powered off for a long time, and therefore, great loss is caused to transportation and national economy.
According to the existing ice melting technology level, an alternating current short circuit ice melting method and a direct current power supply ice melting method are two reliable methods for large-scale power grids. In the alternating-current short-circuit ice melting mode, the low-voltage side of the transformer needs to be connected into an ice melting circuit, a bus PT cabinet and a lightning arrester need to be detached in the field actual operation, and meanwhile, when the ice-coated lines at different distances are dealt with, frequency conversion equipment needs to be additionally applied, so that the circuit is complex. When the alternating-current ice melting method is used for melting ice on an alternating-current line and a direct-current transmission line with the voltage of over 220kV, the effect is not obvious, the impact on a system is large, and the instability of the operation of a power grid can be caused.
At present, when the ice of an overhead line is melted by using direct current, alternating current is rectified and then boosted on a bus to provide injection voltage by depending on VSC equipment. The ice melting scheme has large equipment investment, and not only needs to perform reactive compensation on a system, but also needs to eliminate harmonic waves generated in the working process of devices such as VSC (voltage source converter).
The electric main wiring of the system of 110kV and above adopts a double-bus wiring mode to improve the power supply reliability of users, and a bypass bus is configured to replace an outgoing line breaker with the bypass breaker when the outgoing line breaker breaks down and is overhauled, and the power is supplied to a load through the bypass bus. Traditional VSC ice-melt equipment carries out ice-melt operation to the icing section for realizing the ice-melt that does not have a power failure, closes bypass and bus tie circuit breaker, utilizes bypass generating line to guarantee that system normal power supply, realizes the ice-melt that does not have a power failure through the switch operation.
When a direct-current ice melting mode is adopted, a rectifying device is additionally arranged at the outlet of the bus, and 220kV alternating current is rectified into direct current meeting the requirements of a line to perform thermal ice melting. And the ice melting operation without power outage is realized for ice coating, the three phases of the bus-tie isolating switch are switched off, the bypass bus ensures the normal power supply of the system, and the ice melting without power outage is realized through the operation of the disconnecting link. The existing uninterrupted DC ice melting scheme has the following defects: (1) VSC rectification equipment needs to be additionally arranged at the bus outlet of the substation, and the equipment is expensive and difficult to maintain; (2) when the rectifying equipment works, a large number of power electronic devices are used, a large number of harmonic waves can be generated, and the power supply quality is influenced; (3) during the specific operation, frequent knife switch operation is required
When the energy storage capacity of the lithium battery in the new energy electric automobile is reduced to be below 80% of the initial capacity, the motor efficiency and the endurance mileage of the new energy electric automobile are obviously reduced and face to replacement and elimination, but the energy storage capacity of the lithium battery still has great utilization value. In the prior art, the gradient utilization of the retired lithium battery is mainly applied to the aspect of large-scale integrated energy storage, and a complex BMS system is required to be applied to monitor the state of the lithium battery; the retired lithium battery is rarely applied to the ice melting aspect of high-voltage lines and power transmission lines.
Disclosure of Invention
Aiming at the defects of the method, the invention provides an ice melting device and method based on a retired lithium battery, which can combine the utilization of retired lithium battery in steps with a direct-current ice melting technology, complete ice melting within a specified time and greatly save ice melting cost.
The technical scheme adopted for solving the technical problems is as follows:
on one hand, the de-service lithium battery-based ice melting device provided by the embodiment of the invention comprises a de-service lithium battery, a split conductor, a short-circuit bar and a temperature control switch, wherein the de-service lithium battery, the short-circuit bar and a line to be de-iced form a direct-current ice melting loop through two sub-conductors of the split conductor, and the temperature control switch is arranged in the direct-current ice melting loop at one end of the anode of the de-service lithium battery.
As a possible implementation manner of this embodiment, two ends of the line to be de-iced are respectively connected in series with a short-circuit bar and then connected with two sub-conductors of the split conductor.
As a possible implementation manner of this embodiment, the shorting bar is made of red copper.
As a possible implementation manner of this embodiment, the two sub-wires of the split conductor have the same length.
On the other hand, the ice melting method based on the retired lithium battery provided by the embodiment of the invention comprises the following steps:
forming a direct-current ice melting loop by the retired lithium battery, the 2 short-circuit bars and the line to be melted through the two sub-wires of the split conductor, and arranging a temperature control switch in the direct-current ice melting loop;
calculating ice melting current, closing the temperature control switch to melt ice on the ice-coated line by heating power, and opening the temperature control switch after the ice layer falls off;
and calculating the wire protection current, and automatically closing the temperature control switch when the air temperature is lower than the set temperature of the wire protection current.
As a possible implementation manner of this embodiment, the short-circuit bars are disposed at two ends of the line to be thawed and connected to the two sub-conductors of the split conductor, and the two sub-conductors of the split conductor have the same length.
As a possible implementation manner of this embodiment, the temperature control switch is disposed in the dc ice melting loop at one end of the positive electrode of the retired lithium battery.
As a possible implementation manner of this embodiment, the calculation formula of the ice-melting current is:
where ρ isiceTaking the density of ice to be 0.9g/cm3(ii) a r is the radius of the overhead line, l is the distance from the inner core of the lead to the outside of the ice layer, and (l-r) is the thickness (mm) of the ice-coated ice cylinder; rT0Equivalent thermal conduction resistance (DEG C. cm/W) of ice layer, RT1Equivalent thermal resistance (DEG C cm/W) for convection and radiation; Δ T is the difference between the heated wire temperature and the ambient temperature, TmaxThe highest temperature of the line during ice melting; LGJ-300/40 type (19.6) for thermal expansion coefficient of wire×10-6/℃)；R0The resistance per unit length of the overhead wire (omega/m) at 0 ℃ is obtained.
As a possible implementation manner of this embodiment, the calculation formula of the time for thermally melting ice on the ice-covered line is as follows:
where ρ isiceTaking the density of ice to be 0.9g/cm3(ii) a r is the radius of the overhead line, l is the distance from the inner core of the lead to the outside of the ice layer, and (l-r) is the thickness (mm) of the ice-coated ice cylinder; rT0Equivalent thermal conduction resistance (DEG C. cm/W) of ice layer, RT1Equivalent thermal resistance (DEG C cm/W) for convection and radiation; Δ T is the difference between the heated wire temperature and the ambient temperature, TmaxThe highest temperature of the line during ice melting; the LGJ-300/40 type is (19.6X 10) as the thermal expansion coefficient of the lead wire-6/℃)；R0The resistance per unit length of the overhead wire (omega/m) at 0 ℃ is obtained.
As a possible implementation manner of this embodiment, the calculation formula of the protection current is:
wherein, the delta T' is the temperature difference between the ambient temperature and 0 ℃; k is the heat of fusion of ice (the amount of heat that ice needs to absorb per unit mass of ice when melting), and K is 3.35 × 10-5J/kg；ctThe specific heat capacity of the steel-cored aluminum strand; rhotThe density of the steel-cored aluminum strand; t is tpTo preserve line current operating time.
The technical scheme of the embodiment of the invention has the following beneficial effects:
according to the low-cost characteristic of the retired lithium battery, the retired battery is recycled and recombined into a direct-current power supply in a gradient manner on the basis of considering the output efficiency of the retired lithium battery in a low-temperature environment; and determining a scheme of short-distance interval setting suitable for the actual working condition to ensure the ice melting efficiency of the ice melting device.
Aiming at the gradient utilization of the retired lithium battery, the invention utilizes the retired lithium battery for the secondary ice melting work of the high-voltage transmission line, not only can the ice melting work be completed within the specified time, but also the ice melting cost can be greatly saved. When the high-voltage transmission line adopts a split conductor form, the ice melting loop can be formed by the short circuit spacing rod to perform ice melting work, and the direct-current ice melting current cannot flow out of the loop. When designing the direct-current ice melting parameters, on the basis of considering the research of the low-temperature output characteristics of the retired lithium battery and the influence of factors of battery degradation, improving an ice melting parameter calculation formula; according to the uninterrupted ice melting wiring mode, ice melting current observation and an overhead line environment temperature field simulation test are carried out, and the designed ice melting power supply efficiency is proved to meet the design requirement. The invention utilizes the retired lithium battery as the ice melting power supply, can solve the problem of echelon utilization after a large amount of retired lithium batteries, and realizes secondary utilization of the retired lithium batteries in a power grid.
Description of the drawings:
FIG. 1 is a schematic diagram illustrating an ice melting apparatus based on retired lithium batteries in accordance with an exemplary embodiment;
FIG. 2 is a schematic diagram of three-phase current waveforms during ice melting;
FIG. 3 is a schematic diagram of a boost station bus voltage during ice melting;
FIG. 4 is a schematic diagram of bus voltage of a step-down station in an ice melting process;
FIG. 5 is a temperature profile of an overhead line during ice melting;
FIG. 6 is a schematic diagram of the open circuit voltage variation with time in a low temperature environment of a decommissioned lithium battery;
fig. 7 is a schematic diagram of SOH change in a low-temperature environment of an ex-service lithium battery.
Detailed Description
The invention is further illustrated by the following examples in conjunction with the accompanying drawings:
in order to clearly explain the technical features of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings. The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and procedures are omitted so as to not unnecessarily limit the invention.
Fig. 1 is a schematic diagram illustrating an ice melting apparatus based on a retired lithium battery according to an exemplary embodiment. As shown in fig. 2, the de-service lithium battery-based ice melting device provided by the embodiment of the invention comprises a de-service lithium battery, a split conductor, a short-circuit bar and a temperature-controlled switch, wherein the de-service lithium battery, the short-circuit bar and a line to be de-iced form a direct-current ice melting loop through two sub-conductors of the split conductor, and the temperature-controlled switch is arranged in the direct-current ice melting loop at one end of the anode of the de-service lithium battery.
Aiming at the problem that effective echelon utilization is difficult to realize due to the fact that a large number of lithium batteries in a new energy automobile are retired, the invention combines secondary utilization of retired lithium batteries with a direct-current ice melting technology and is applied to ice melting work of a high-voltage overhead line. Aiming at the phenomenon that the power transmission line is easily covered with ice in southern areas, northeast areas and mountain forest areas, the cost of the direct-current ice melting device and the output power and capacity of the battery energy storage unit are considered, and the ice melting device utilizing the energy stored by the retired lithium batteries can be utilized in a gradient manner by combining the retirement of a large number of lithium batteries in a new energy automobile.
The design process of the direct-current ice melting power supply based on secondary utilization of the retired lithium battery is as follows.
1. Calculating ice melting parameters:
(1) ice melting current
According to the national power grid 'electric transmission line current ice melting technical guide', the ice melting equipment needs to have two functions, namely, providing line protection current and ice melting current, according to the principle of 'melting and bonding resistance' in the working mode of the direct current ice melting power supply. When calculating the ice melting current, the selection of the environmental temperature should be considered according to the local average lowest temperature. When the ambient or line temperature in the range of overhead line heat radiation is continuously higher than 0 ℃, the ice on the line will be melted and de-iced. In order to improve the ice melting efficiency, the maximum ice melting current is set according to the technical guide rule, and the steel-cored aluminum strand is prevented from expanding and deforming due to overhigh temperature to generate permanent damage, so that the temperature limit (70-90 ℃) of the overhead line and the thermal expansion coefficient of the overhead line are considered during calculation. By utilizing the law of conservation of energy and considering the heat radiation loss, the blackness of the lead (the external heat radiation of the lead) and the thermal expansion coefficient of the overhead line, a calculation formula of the ice melting current can be obtained, and the formula is shown in formula (1).
Where ρ isiceTaking the density of ice to be 0.9g/cm3(ii) a r is the radius of the overhead line, l is the distance from the inner core of the lead to the outside of the ice layer, and (l-r) is the thickness (mm) of the ice-coated ice cylinder; rT0Equivalent thermal conduction resistance (DEG C. cm/W) of ice layer, RT1Equivalent thermal resistance (DEG C cm/W) for convection and radiation; Δ T is the difference between the heated wire temperature and the ambient temperature, TmaxThe highest temperature of the line during ice melting; the LGJ-300/40 type is (19.6X 10) as the thermal expansion coefficient of the lead wire-6/℃)。R0The resistance per unit length of the overhead wire (omega/m) at 0 ℃ is obtained.
(2) Ice melting time:
the ice melting time calculation formula can fully embody two processes of ice melting of the overhead line: firstly, the temperature of the overhead line rises to 0 ℃ and reaches a critical melting point; secondly, the overhead line is continuously heated, and the ice coating layer begins to absorb heat and melt. The ice melting process of the power transmission line is a variable parameter transient temperature field problem, the relation of temperature change along with space and time is complex, the traditional ice melting is refined into two stages of line temperature rise and joule heat radiation ice melting, and an ice melting time calculation formula (2) under the condition that the conduction of an equivalent ice layer and the loss of external heat radiation of an overhead line are considered can be obtained.
(3) The wire protection current:
the direct-current ice melting equipment needs to have the functions of melting and bonding resistance, resist ice and snow disaster weather, provide the line protection current as the minimum current for protecting a line from ice coating in extreme weather, balance the heat generated by the line protection current through a wire with the heat to be consumed, and have the calculation formula (3). The holding temperature is generally designed to be above 0 ℃ (generally 2 ℃).
Wherein, the delta T' is the temperature difference between the ambient temperature and 0 ℃; k is the heat of fusion of ice (the amount of heat that ice needs to absorb per unit mass of ice when melting), and K is 3.35 × 10-5J/kg；ctThe specific heat capacity of the steel-cored aluminum strand; rhotThe density of the steel-cored aluminum strand; t is tpTo preserve line current operating time.
2. Designing an ice melting power supply:
in the AC ice melting mode or the DC ice melting mode, when the ice melting line is too long, the required voltage is too high during ice melting, and the capacity of the transformer is too large. The direct-current ice melting power supply adopting the retired lithium battery is low in price, economical and suitable for a short-distance and multi-interval ice melting mode.
By combining the geographic environment of the ice melting section and historical meteorological data, the capacity characteristic of the retired lithium battery is considered (the capacity is 80% of the initial capacity during retirement), the polarization reaction and the capacity attenuation inside the lithium battery are accelerated by considering the increase along with the use time and the rate discharge during ice melting, and therefore a certain margin is reserved when the capacity of the ice melting power supply is set. The ice melting time of the LGJ-300/40 model conductor, the ice melting current amplitude and the ice melting power supply capacity under the corresponding overhead line length are referenced according to Table 1. The invention takes a 5km two-split ice-covered overhead line (0.09211 omega/km) and an ice melting power supply outputting 1kA direct current as an example, and the capacity of a lithium battery is considered to decline, a 20% capacity margin is set, and the capacity of the retired lithium battery direct current ice melting power supply is about 1.15 MW.
TABLE 1 LGJ-300/40 type overhead line Ice melting parameters
Taking 18650 model batteries as an example, the retired lithium battery is recombined into a 1.2WM ice melting power supply. The 18650 type ternary lithium batteries adopted in different brands of new energy automobiles have different standard capacities, the average capacity is 3000mAh, and the average mass is 40-50 g; considering that the decommissioning condition of the lithium battery is 75-80% of the initial capacity, and calculating according to the attenuation to 75% of SOH, 12500 18650 batteries are needed, 20% allowance is set according to the battery attenuation, 36 groups of battery packs are designed, and every 350 batteries are a group; the mass of the retired lithium battery in the direct-current ice melting power supply is about 1600 kg. The batteries are arranged in a crossed and compact mode, the size of a single lithium Battery pack is 10 multiplied by (180 multiplied by 70 multiplied by 51mm), the occupied volume of the Battery is 0.237762m3, and the size of a power supply is about 0.3m3 in consideration of the space occupied by a Battery Management System (BMS) and a disconnecting switch for protecting.
The ice melting time is ensured to be within the range of the requirement of national grid ice melting technical criteria, and an excessively high ice melting current cannot be set for the purpose of improving the ice melting efficiency, otherwise, the problems of line voltage rising and insulation damage can be caused. As shown in fig. 2, the waveforms of the three-phase currents in the ice melting process show that when the dc power supply is connected to perform the wire protection and ice melting operation, the three-phase currents are maintained stable, and the ice melting phase currents are obviously transited, so as to meet the ice melting requirement.
In order to further observe the influence of the ice melting current on the stability of the other two-phase voltage when the ice melting power supply carries out ice melting operation on one phase of circuit, the voltage waveform on the bus of the booster station needs to be observed; the voltage of the user terminal cannot deviate too much, otherwise, the voltage quality of the user terminal is affected, and therefore, the voltage waveform on the bus of the voltage reduction station also needs to be observed. As shown in fig. 3 and 4, the influence of access of the ice melting power supply on the transformer substation side and the user side can be ignored when three-phase voltage waveforms are applied to the high-voltage buses on the booster station side and the buck station side, Fast Fourier Transform (FFT) harmonic wave observation modules are built by using PSCAD simulation software, the three-phase voltage distortion rate is monitored, and the single-phase total harmonic distortion rate can be found to be less than 0.328% and can be almost ignored.
And simulating the ice melting process of the overhead line with corresponding model data by utilizing COMSOL software under the conditions of a low-temperature environment of-10 ℃ and an ice cylinder of 10mm covered on the overhead line to obtain the temperature field change of the overhead line. Under ideal conditions, when the ice melting power supply works, the temperature of the overhead line changes, and when the ice melting current reaches 988.54A, as shown in fig. 5, the maximum temperature of the ice coating contact layer reaches 66.58 ℃, the internal temperature of the overhead line is 82.86 ℃, and the overhead line works within reasonable temperature limits.
The design process of the direct-current deicing power supply based on secondary utilization of the retired lithium battery needs the following matters.
1. Considering the wire thermal expansion coefficient:
the ice coating layer undergoes the following processes in the melting process: temperature rise of the lead → melting (liquefaction) of the ice cylinder → latent heat of vaporization → completion of ice melting. The lead additionally absorbs heat energy released by the overhead line in the process of latent heat vaporization, so that water formed by melting the inner wall of the ice cylinder is evaporated, and when the energy absorbed in the evaporation process is ignored, the selected ice melting current is too small, ice melting work cannot be completed within a rated time, and the efficiency of an ice melting power supply is reduced. Therefore, in calculating the ice-melt current, R should be conducted while taking into account the coefficient of thermal expansion of the wireT0、RT1The temperature difference range is set as the maximum value, and the influence of the wind speed in the local low-temperature environment is also considered, so that a certain margin is set for selecting the capacity of the direct-current power supply, as shown in formula (4) and formula (5).
VwindThe synchronous wind speed is m/s when the ice melts; lambda is the ice coating thermal conductivity, and the ice is 0.0227 for rime and 0.0012 for rime. Generally, the black degree of the conductor (emissivity coefficient of the split conductor) is 0.22-0.43 for the new conductor and 0.9 for the old conductor.
2. Considering the low-temperature output characteristic of the retired lithium battery:
the new energy automobile generally adopts a ternary lithium battery, and the new energy automobile takes a 18650 type ternary lithium battery (the proportion of nickel salt, cobalt salt and manganese salt is 6:2:2) as an example, the nominal voltage is 3.7V, the float charge voltage of charge cut-off is 3.9-4.2V, and the lowest output is 2.5V. Fitting the retired ternary lithium battery of the passenger automobile in a random battery use data set (RBUD) by using COMSOL physical simulation software in combination with retired lithium battery data provided by a NASA PCoE research center of the United states of America and space administration; and the aging degree of the retired battery is simulated by changing the particle sizes of positive and negative electrode material particles, the thickness of a Solid Electrolyte Interface (SEI), the porosity of the electrode material and the volume fraction of electrolyte of the retired ternary lithium battery under different states of charge (SOC). The working environment temperature of the retired lithium battery was changed, and set to-20 deg.C, -10 deg.C, 0 deg.C and 25 deg.C, respectively, as compared with the voltage drop of 1000 charge-discharge cycles in a low temperature environment, as shown in FIG. 6.
Under four environmental temperatures, the degradation condition of Open Circuit Voltage (OCV) and the attenuation of state of health (SOH) of the retired ternary lithium battery during the charge and discharge cycle are simulated, and as can be seen from the data in table 2, when the open circuit voltage is reduced to 2.5V (the cut-off voltage of the lithium battery), the battery discharge time is about 2800s at the standard working temperature of 25 ℃. At a relatively ideal temperature; under the standard discharge rate of 1C, the environment of low temperature of-20 ℃ in a simulated season is realized, the discharge time is 2048s, and the discharge time is reduced by 27.84% relative to the standard working condition; discharge to a cut-off voltage of 94.01% at-10 ℃ at 25 ℃.
TABLE 2 decommissioned lithium batteries open circuit voltage drop
In the direct-current ice melting mode, a direct-current power supply formed by recombination of the retired lithium battery needs to output larger current within a specified time for rapid ice melting, the ice melting current range of the (LGJ-300/40) type conducting wire is 700-1200A, and the SOH change of the retired lithium battery under the conditions of different environmental temperatures and high-rate discharge is analyzed; and (3) comparing the temperature (25 ℃) of the new energy automobile with the temperature in a standard environment, verifying whether the health state of the retired lithium battery can meet the working requirement of the direct-current ice melting power supply, and simulating 4C charge-discharge circulation of the ternary lithium battery after the new energy automobile is retired to 80% of the initial capacity.
In COMSOL simulation software, SOH change of the retired lithium battery under a low-temperature environment is simulated. From the analysis of FIG. 7, it can be seen that:
(1) the initial SOH at 0 ℃ is close to 75%, and the decline of the health state is mild.
(2) After nearly 300 charge-discharge cycles at-10 ℃, the SOH decayed to 58.37% under the brand new condition.
(3) When the ambient temperature is reduced to-20 ℃, the health state of the retired lithium battery is obviously reduced within 500 cycles, and the state is reduced to 46.07% of the initial SOH.
However, the ice melting power supply is used for a few times, and only the low-temperature weather of extreme rime and rime is needed to be dealt with, so that the retired lithium battery of the new energy passenger vehicle under the test meets the working requirement of the direct-current power supply.
3. Deicing split conductors by using short circuit spacers:
the existing direct-current ice melting power supply mostly adopts a mobile power supply vehicle form, the mobile power supply vehicle (or an emergency power supply vehicle) needs to be driven to the lower part of an ice melting line during ice melting, and the mobile direct-current power supply vehicle is difficult to reach in mountain and forest areas with high air humidity and low temperature at night. In addition, the mobile power car needs to be matched with a set of fixed direct current source converter (VSC) or 6/12 pulse rectifier, which is too high in cost and cannot achieve good economic benefit.
At present, in order to reduce skin effect, inhibit corona discharge and reduce line reactance in a high-voltage power transmission network, an overhead line mostly adopts a split conductor form. Aiming at an overhead line adopting a split conductor form, according to the principle that the potentials of all phases of sub-conductors of a split conductor in the classic transmission line theory are equal, a direct-current ice melting power supply, two sub-conductors of the split conductor and a short-circuit rod form a direct-current ice melting loop, and an ice-covered line in an ice melting section is heated by using a direct-current ice melting current and a line load current together, so that the ice melting effect is achieved, and the impedance matching and load transfer of the ice-covered line are not needed in the working process.
The principle of the scheme for designing the ice melting power supply is shown in figure 1 by taking lGJ-300/40 split conductors as an example. Two short-circuit bars (mainly used for leading direct current) made of good conductors are arranged at two ends of the section needing to be melted. The two sub-conductors corresponding to each phase of circuit have equal potential, so that the two sub-conductors can be regarded as equipotential surfaces, and when the direct-current ice-melting power supply is in a non-working state, the positive electrode and the negative electrode of the direct-current ice-melting power supply are respectively connected with the two sub-conductors. Taking the C-phase ice melting of a binary-split overhead line as an example, direct current flows into a power transmission line from an ice melting power supply and flows through a short-circuit rod, the lines needing ice melting are connected in series to form an ice melting loop, the direct current flows in the loop of the ice melting power supply, the line and the short-circuit rod, and the temperature of the ice-coated line is raised by the heat effect of the current, so that the aim of melting ice is fulfilled.
As shown in fig. 1, the ice melting device mainly comprises a retired lithium battery, a short-circuit bar and a temperature control switch.
Firstly, decommissioning the lithium battery: and outputting direct current to provide ice melting current and wire protection current.
Secondly, temperature control switch: the temperature control switch is closed when ice melting operation is needed, and when the air temperature is lower than a set temperature (for example, -10 ℃, the temperature needs to be set according to the environmental temperature data when the ice coating phenomenon of a local power grid occurs) occurs in winter, the switch is automatically closed to provide line protection current.
③ short-circuit bars 1, 2: the red copper short-circuit rod is adopted, the minimum resistance is 0.0172 omega/m, the maximum outer diameter is 150mm, the tolerance temperature meets the temperature limit requirement during ice melting, is about 100 ℃, and exceeds the highest temperature of an overhead line during ice melting. The direct current ice melting circuit is erected at the beginning and the beginning of the ice coating circuit to ensure that the direct current ice melting current does not flow out of a loop.
The specific operation steps of the ice melting by using the method provided by the invention are as follows:
firstly, the ice melting power supply can be installed on a 220kV tower in a fixed mode, is connected by a short-distance cable or a cable joint, and is provided with a temperature control switch on a power supply wiring.
Secondly, assuming that the length of the ice coating section is l (km), installing the short-circuit bars 1 and 2 on the two-split overhead line (the installation mode needs manual operation for installation), and ensuring that the positive pole and the negative pole of the power supply are connected into two overhead lines with equal length (l) in parallel.
Thirdly, closing the temperature control switch to enable the ice melting power supply to output the ice melting current calculated by the formula (1), melting ice on the ice-covered line by heating power, and disconnecting the temperature control switch after the ice layer falls off
Fourthly, the temperature control switch is automatically closed when the ice coating is easy to occur in winter and the air temperature is lower than the set working temperature of the wire protection current, the wire protection current calculated by the formula (3) is output, and the ice coating of the line is avoided
After the ice melting operation is finished, the working personnel disconnects the detached power supply connection and the short-circuit bar, and the invention utilizes the retired lithium battery in the DC ice melting operation in a gradient manner, thereby improving the recycling rate of the retired battery and widening the utilization path of the retired battery. For the secondary service life of the lithium battery, although the energy efficiency ratio does not meet the economic operating condition of the electric automobile any more, when the lithium battery is secondarily used in a transmission network and a distribution network, the conditions of residual capacity, open-circuit voltage and energy density still meet the operating requirement of the power grid.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (10)
1. The de-service lithium battery-based ice melting device is characterized by comprising a de-service lithium battery, a split conductor, a short circuit bar and a temperature control switch, wherein the de-service lithium battery, the short circuit bar and a line to be de-iced form a direct-current ice melting loop through two sub-conductors of the split conductor, and the temperature control switch is arranged in the direct-current ice melting loop at one end of the anode of the de-service lithium battery.
2. The retired lithium battery-based ice melting device of claim 1, wherein two ends of the line to be melted are respectively connected with two sub-conductors of the split conductor after being connected with a short-circuit bar in series.
3. The retired lithium battery-based ice melting device of claim 1, wherein the short-circuit bars are made of red copper.
4. The retired lithium battery-based ice melting device of claim 1, wherein the two sub-conductors of the split conductor are the same length.
5. A de-icing method based on a retired lithium battery is characterized by comprising the following steps:
forming a direct-current ice melting loop by the retired lithium battery, the 2 short-circuit bars and the line to be melted through the two sub-wires of the split conductor, and arranging a temperature control switch in the direct-current ice melting loop;
calculating ice melting current, closing the temperature control switch to melt ice on the ice-coated line by heating power, and opening the temperature control switch after the ice layer falls off;
and calculating the wire protection current, and automatically closing the temperature control switch when the air temperature is lower than the set temperature of the wire protection current.
6. The ex-service lithium battery-based ice melting method according to claim 5, wherein the short-circuit bars are arranged at two ends of the line to be melted and connected with the two sub-conductors of the split conductor, and the two sub-conductors of the split conductor have the same length.
7. The retired lithium battery-based ice melting method according to claim 5, wherein the temperature controlled switch is arranged in a direct current ice melting loop at one end of a positive electrode of the retired lithium battery.
8. The retired lithium battery-based ice melting method according to any one of claims 5 to 7, wherein the calculation formula of the ice melting current is as follows:
where ρ isiceTaking the density of ice to be 0.9g/cm3(ii) a r is the radius of the overhead line, l is the distance from the inner core of the lead to the outside of the ice layer, and (l-r) is the thickness (mm) of the ice-coated ice cylinder; rT0Equivalent thermal conduction resistance (DEG C. cm/W) of ice layer, RT1Equivalent thermal resistance (DEG C cm/W) for convection and radiation; Δ T is the difference between the heated wire temperature and the ambient temperature, TmaxThe highest temperature of the line during ice melting; the LGJ-300/40 type is (19.6X 10) as the thermal expansion coefficient of the lead wire-6/℃)；R0The resistance per unit length of the overhead wire (omega/m) at 0 ℃ is obtained.
9. The retired lithium battery-based ice melting method according to any one of claims 5 to 7, wherein the calculation formula of the thermal ice melting time of the ice-covered line is as follows:
where ρ isiceTaking the density of ice to be 0.9g/cm3(ii) a r is the radius of the overhead line, l is the distance from the inner core of the lead to the outside of the ice layer, and (l-r) is the thickness (mm) of the ice-coated ice cylinder; rT0Equivalent thermal conduction resistance (DEG C. cm/W) of ice layer, RT1Equivalent thermal resistance (DEG C cm/W) for convection and radiation; Δ T is the difference between the heated wire temperature and the ambient temperature, TmaxThe highest temperature of the line during ice melting; the LGJ-300/40 type is (19.6X 10) as the thermal expansion coefficient of the lead wire-6/℃)；R0The resistance per unit length of the overhead wire (omega/m) at 0 ℃ is obtained.
10. The retired lithium battery-based ice melting method according to any one of claims 5 to 7, wherein the wire protection current is calculated by the following formula:
wherein, the delta T' is the temperature difference between the ambient temperature and 0 ℃; k is the heat of fusion of ice (the amount of heat that ice needs to absorb per unit mass of ice when melting), and K is 3.35 × 10-5J/kg；ctThe specific heat capacity of the steel-cored aluminum strand; rhotThe density of the steel-cored aluminum strand; t is tpTo preserve line current operating time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010891754.6A CN112054466A (en) | 2020-08-28 | 2020-08-28 | De-service lithium battery-based ice melting device and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010891754.6A CN112054466A (en) | 2020-08-28 | 2020-08-28 | De-service lithium battery-based ice melting device and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112054466A true CN112054466A (en) | 2020-12-08 |
Family
ID=73607641
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010891754.6A Pending CN112054466A (en) | 2020-08-28 | 2020-08-28 | De-service lithium battery-based ice melting device and method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112054466A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101272041A (en) * | 2008-04-14 | 2008-09-24 | 朱发国 | Wire-protecting and de-icing method of unit type high tension power line |
| US20090250449A1 (en) * | 2008-04-02 | 2009-10-08 | The Trustees Of Dartmouth College | System And Method For Deicing Of Power Line Cables |
| CN105406433A (en) * | 2016-01-23 | 2016-03-16 | 国网福建省电力有限公司 | Optimal power and capacity selection method of mobile battery energy storage DC-based deicing system |
| CN105826889A (en) * | 2015-01-08 | 2016-08-03 | 罗日成 | Transmission line charged segmented DC ice melting method |
| CN106786298A (en) * | 2016-11-16 | 2017-05-31 | 国网山东省电力公司荣成市供电公司 | A kind of self-heating deicing system of high-tension transmission lines |
| CN108832539A (en) * | 2018-07-27 | 2018-11-16 | 贵州电网有限责任公司 | A kind of online de-icing method using the energy storage device optimization transmission line of electricity method of operation |
| CN109449854A (en) * | 2018-12-06 | 2019-03-08 | 四川大学 | Station lossless three-phase current divider and design and control method for anti-icing ice-melt |
-
2020
- 2020-08-28 CN CN202010891754.6A patent/CN112054466A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090250449A1 (en) * | 2008-04-02 | 2009-10-08 | The Trustees Of Dartmouth College | System And Method For Deicing Of Power Line Cables |
| CN101272041A (en) * | 2008-04-14 | 2008-09-24 | 朱发国 | Wire-protecting and de-icing method of unit type high tension power line |
| CN105826889A (en) * | 2015-01-08 | 2016-08-03 | 罗日成 | Transmission line charged segmented DC ice melting method |
| CN105406433A (en) * | 2016-01-23 | 2016-03-16 | 国网福建省电力有限公司 | Optimal power and capacity selection method of mobile battery energy storage DC-based deicing system |
| CN106786298A (en) * | 2016-11-16 | 2017-05-31 | 国网山东省电力公司荣成市供电公司 | A kind of self-heating deicing system of high-tension transmission lines |
| CN108832539A (en) * | 2018-07-27 | 2018-11-16 | 贵州电网有限责任公司 | A kind of online de-icing method using the energy storage device optimization transmission line of electricity method of operation |
| CN109449854A (en) * | 2018-12-06 | 2019-03-08 | 四川大学 | Station lossless three-phase current divider and design and control method for anti-icing ice-melt |
Non-Patent Citations (3)
| Title |
|---|
| 刘坚: ""电动汽车退役电池储能应用潜力及成本分析"", 《储能科学与技术》 * |
| 敬华兵，年晓红: ""输电线路柔性直流融冰技术"", 《高电压技术》 * |
| 王朗珠，杨绍远，郑连清: ""500kV变电站的直流融冰技术研究"", 《华北电力大学学报》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA3024347C (en) | Traction power supply system for high speed train and its on-board power storage and discharge system | |
| CN101877470B (en) | Direct current thawing apparatus with special rectiformer and protection method thereof | |
| Juanjuan et al. | Research and application of DC de–icing technology in china southern power grid | |
| Geiles et al. | Impact of PEV charging and rooftop PV penetration on distribution transformer life | |
| CN103219766B (en) | Non-floating charge lithium electricity type station DC power system | |
| Han et al. | A review on development practice of smart grid technology in China | |
| Kazerooni et al. | Impact analysis of EV battery charging on the power system distribution transformers | |
| CN103117595B (en) | Distributed direct current independent power supply system | |
| CN210927503U (en) | Photovoltaic power generation and energy storage integrated power supply system | |
| CN103474987B (en) | Electric transmission line on-line monitoring device energy obtaining system based on ground wire induction | |
| Zhu et al. | Research on melting and de-icing methods of lines in distribution network | |
| CN111049468A (en) | Photovoltaic power generation and energy storage integrated power supply system and method | |
| CN203119615U (en) | Distributed direct-current independent power supply system | |
| CN112102984A (en) | Novel steel core ice melting insulated wire and ice melting system and method thereof | |
| Dai et al. | Transmission technologies and implementations: Building a stronger, smarter power grid in China | |
| Liu et al. | The field experience of a dynamic rating system on overhead power transmission lines | |
| CN110932215A (en) | System and method for deicing overhead line by using photovoltaic power generation | |
| Wang et al. | Design on DC de-icing schemes for high voltage transmission line | |
| CN112054466A (en) | De-service lithium battery-based ice melting device and method | |
| CN102299499A (en) | Ice melting scheme of circuit alternating-current short circuit after voltage reduction for 10kV power supply through 35kV main transformer | |
| Sonder et al. | Voltage analysis on MV/LV distribution networks with the integration of DC fast chargers | |
| Sonder et al. | Using electric vehicles and demand side response to unlock distribution network flexibility | |
| CN103117596B (en) | Distributed direct-current power supply system for substation | |
| CN203119617U (en) | Distributed direct-current independent power supply system for transformer substation | |
| Latyshev et al. | Charging stations for electric cars using hybrid energy storage systems |
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 | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20201208 |