CN104730388A - Method and device for evaluating influence of environment thermal resistance on three-core cable core temperature - Google Patents

Method and device for evaluating influence of environment thermal resistance on three-core cable core temperature Download PDF

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CN104730388A
CN104730388A CN201510133843.3A CN201510133843A CN104730388A CN 104730388 A CN104730388 A CN 104730388A CN 201510133843 A CN201510133843 A CN 201510133843A CN 104730388 A CN104730388 A CN 104730388A
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core
thermal resistance
temperature
core cable
laying
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胡日鹏
王鹏
陈艺璇
刘刚
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South China University of Technology SCUT
Guangzhou Power Supply Bureau Co Ltd
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Guangzhou Power Supply Bureau Co Ltd
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Abstract

本发明涉及一种环境热阻影响三芯电缆线芯温度的评估方法及装置。所述方法包括步骤:根据三芯电缆的热路模型,得到空气敷设下的环境热阻和/或土壤敷设下的环境热阻;根据三芯电缆的热路模型,得到三芯电缆的线芯温度;若三芯电缆为空气敷设,根据空气敷设下的环境热阻与环境温度的关系以及确定线芯温度对空气敷设下的环境热阻的灵敏度;若三芯电缆为土壤敷设,根据确定线芯温度对土壤敷设下的环境热阻的灵敏度。本发明能够准确分析环境热阻对三芯电缆线芯温度影响程度;根据空气敷设或土壤敷设时的灵敏度大小,在三芯电缆加载电流较大时,尤其是三芯电缆的敷设为空气辐射时,加大环境温度的监测力度,从而保证电力线缆的安全稳定运行。

The invention relates to a method and a device for evaluating the influence of environmental thermal resistance on the core temperature of a three-core cable. The method comprises the steps of: obtaining the environmental thermal resistance under air laying and/or the environmental thermal resistance under soil laying according to the thermal circuit model of the three-core cable; obtaining the wire core of the three-core cable according to the thermal circuit model of the three-core cable temperature; if the three-core cable is laid by air, according to the relationship between the ambient thermal resistance and the ambient temperature under air laying and Determine the sensitivity of the wire core temperature to the environmental thermal resistance under air laying; if the three-core cable is laid in soil, according to Determine the sensitivity of the wire core temperature to the thermal resistance of the environment under soil laying. The invention can accurately analyze the influence degree of environmental thermal resistance on the core temperature of the three-core cable; according to the sensitivity of air laying or soil laying, when the three-core cable is loaded with a large current, especially when the three-core cable is laid by air radiation , Increase the monitoring of the ambient temperature, so as to ensure the safe and stable operation of the power cable.

Description

环境热阻影响三芯电缆线芯温度的评估方法及装置Method and device for evaluating the influence of environmental thermal resistance on the core temperature of three-core cables

技术领域technical field

本发明涉及电力电缆技术领域,特别是涉及一种环境热阻影响三芯电缆线芯温度的评估方法、环境热阻影响三芯电缆线芯温度的评估装置。The invention relates to the technical field of power cables, in particular to an evaluation method for the influence of environmental thermal resistance on the core temperature of a three-core cable and an evaluation device for the influence of environmental thermal resistance on the core temperature of a three-core cable.

背景技术Background technique

电力电缆运行中线芯的温度是确定电力电缆是否达到载流量的依据。而电缆载流量是电缆运行中受环境条件和负荷因素影响的重要动态运行参数,其重要性影响到输电线路的安全可靠、经济合理运行以及电缆寿命等问题。若电缆的载流量偏大,会造成电缆线芯温度的工作温度超过容许值,从而会影响绝缘的寿命;若电缆的载流量偏小,则电缆线芯铜材或铝材就不能得到充分的利用,导致不必要的浪费。The temperature of the wire core during the operation of the power cable is the basis for determining whether the power cable has reached the current carrying capacity. The cable ampacity is an important dynamic operating parameter affected by environmental conditions and load factors during cable operation, and its importance affects the safety and reliability of transmission lines, economical and reasonable operation, and cable life. If the ampacity of the cable is too large, the working temperature of the cable core temperature will exceed the allowable value, which will affect the life of the insulation; if the ampacity of the cable is too small, the copper or aluminum of the cable core will not be fully protected. use, resulting in unnecessary waste.

目前,通过线芯温度推算电缆载流量的方法有多种,如IEC(InternationalElectrotechnical Commission)标准、热路法、模拟热荷法、有限元法和有限差分法等。IEC60287标准是目前较被认可、应用最广的运用传热学原理计算电缆载流量的解析算法,许多学者提出来的热路模型基本上都是在IEC标准提出来的热路模型上进行的改进。但是由于实际运行中电缆线路的载流能力受到诸多因素的影响,例如外部环境(环境温度和环境热阻等),而IEC60287系列标准在载流量计算过程中忽略了很多外部因素,所以无法准确计算载流量。另外,国内外将线芯温度对外部环境的灵敏度分析应用于单芯电缆的研究已经趋近成熟,但是由于三芯电缆与单芯电缆结构上的差异,即三芯电缆三相互相影响,结构远远比单芯电缆复杂,所以现有单芯电缆的灵敏度分析无法应用到三芯电缆。为了研究外部环境对线芯温度的影响程度,保证电力电缆的安全运行,迫切需要提供一种三芯电缆的灵敏度评估方法。At present, there are many methods for estimating the current carrying capacity of cables through the core temperature, such as the IEC (International Electrotechnical Commission) standard, thermal circuit method, simulated thermal charge method, finite element method and finite difference method. The IEC60287 standard is currently the most recognized and widely used analytical algorithm for calculating the ampacity of cables using the principle of heat transfer. The thermal circuit model proposed by many scholars is basically an improvement on the thermal circuit model proposed by the IEC standard. . However, since the current-carrying capacity of the cable line in actual operation is affected by many factors, such as the external environment (ambient temperature and environmental thermal resistance, etc.), the IEC60287 series standards ignore many external factors in the calculation of the current-carrying capacity, so it cannot be accurately calculated. Ampacity. In addition, the research on applying the sensitivity analysis of the core temperature to the external environment to the single-core cable at home and abroad has become mature. It is far more complex than single-core cables, so the sensitivity analysis of existing single-core cables cannot be applied to three-core cables. In order to study the influence of the external environment on the core temperature and ensure the safe operation of power cables, it is urgent to provide a sensitivity evaluation method for three-core cables.

发明内容Contents of the invention

基于此,有必要针对上述问题,提供一种环境热阻影响三芯电缆线芯温度的评估方法及装置,能够分析环境热阻对三芯电缆线芯温度的影响程度。Based on this, it is necessary to address the above problems and provide a method and device for evaluating the influence of environmental thermal resistance on the core temperature of a three-core cable, which can analyze the degree of influence of environmental thermal resistance on the core temperature of a three-core cable.

一种环境热阻影响三芯电缆线芯温度的评估方法,包括步骤:A method for evaluating the influence of environmental thermal resistance on the core temperature of a three-core cable, comprising steps:

根据三芯电缆的热路模型,得到空气敷设下的环境热阻和/或土壤敷设下的环境热阻;According to the thermal circuit model of the three-core cable, the environmental thermal resistance under air laying and/or the environmental thermal resistance under soil laying is obtained;

根据三芯电缆的热路模型,得到三芯电缆的线芯温度;According to the thermal circuit model of the three-core cable, the core temperature of the three-core cable is obtained;

若三芯电缆为空气敷设,根据空气敷设下的环境热阻与环境温度的关系以及确定线芯温度对空气敷设下的环境热阻的灵敏度;If the three-core cable is laid by air, according to the relationship between the ambient thermal resistance and the ambient temperature under air laying and Determine the sensitivity of the wire core temperature to the ambient thermal resistance under air laying;

若三芯电缆为土壤敷设,根据确定线芯温度对土壤敷设下的环境热阻的灵敏度;If the three-core cable is laid in soil, according to Determine the sensitivity of the wire core temperature to the ambient thermal resistance under soil laying;

其中表示线芯温度对空气敷设下的环境热阻的灵敏度或线芯温度对土壤敷设下的环境热阻的灵敏度,θ1表示线芯温度,T4表示空气敷设下的环境热阻或土壤敷设下的环境热阻。in Indicates the sensitivity of the core temperature to the environmental thermal resistance under air laying or the sensitivity of the core temperature to the environmental thermal resistance under soil laying, θ 1 represents the core temperature, T 4 represents the environmental thermal resistance under air laying or soil laying ambient thermal resistance.

一种环境热阻影响三芯电缆线芯温度的评估装置,包括:An evaluation device for the influence of environmental thermal resistance on the core temperature of a three-core cable, comprising:

环境热阻确定模块,用于根据三芯电缆的热路模型,得到空气敷设下的环境热阻和/或土壤敷设下的环境热阻;The environmental thermal resistance determination module is used to obtain the environmental thermal resistance under air laying and/or the environmental thermal resistance under soil laying according to the thermal circuit model of the three-core cable;

线芯温度确定模块,用于根据三芯电缆的热路模型,得到三芯电缆的线芯温度;The wire core temperature determination module is used to obtain the wire core temperature of the three-core cable according to the thermal circuit model of the three-core cable;

第一灵敏度确定模块,用于在三芯电缆为空气敷设时,根据空气敷设下的环境热阻与环境温度的关系以及确定线芯温度对空气敷设下的环境热阻的灵敏度;The first sensitivity determination module is used for when the three-core cable is laid in air, according to the relationship between the ambient thermal resistance and the ambient temperature under air laying and Determine the sensitivity of the wire core temperature to the ambient thermal resistance under air laying;

第二灵敏度确定模块,用于在三芯电缆为土壤敷设时,根据确定线芯温度对土壤敷设下的环境热阻的灵敏度;The second sensitivity determination module is used for when the three-core cable is laid in soil, according to Determine the sensitivity of the wire core temperature to the ambient thermal resistance under soil laying;

其中表示线芯温度对空气敷设下的环境热阻的灵敏度或线芯温度对土壤敷设下的环境热阻的灵敏度,θ1表示线芯温度,T4表示空气敷设下的环境热阻或土壤敷设下的环境热阻。in Indicates the sensitivity of the core temperature to the environmental thermal resistance under air laying or the sensitivity of the core temperature to the environmental thermal resistance under soil laying, θ 1 represents the core temperature, T 4 represents the environmental thermal resistance under air laying or soil laying ambient thermal resistance.

本发明环境热阻影响三芯电缆线芯温度的评估方法及装置,通过生物学中灵敏度的概念,分析了环境热阻对电缆线芯温度的影响程度,即电缆线芯温度对环境热阻的灵敏度大小。实验研究表明,本发明能够准确分析环境热阻对三芯电缆线芯温度影响程度。另外,根据本发明空气敷设或土壤敷设时的灵敏度大小,得到随着加载电流的增大,线芯温度对外部环境热阻的灵敏度越来越大,所以在三芯电缆加载电流较大时,尤其是三芯电缆的敷设为空气辐射时,应加大环境温度的监测力度,从而保证电力线缆的安全稳定运行。The method and device for evaluating the influence of environmental thermal resistance on the core temperature of a three-core cable in the present invention analyze the influence degree of environmental thermal resistance on the temperature of the cable core through the concept of sensitivity in biology, that is, the effect of the temperature of the cable core on the environmental thermal resistance Sensitivity size. Experimental research shows that the invention can accurately analyze the degree of influence of environmental thermal resistance on the core temperature of a three-core cable. In addition, according to the sensitivity of air laying or soil laying according to the present invention, it is obtained that with the increase of the loading current, the sensitivity of the core temperature to the thermal resistance of the external environment is increasing, so when the loading current of the three-core cable is large, Especially when the laying of the three-core cable is air radiation, the monitoring of the ambient temperature should be strengthened to ensure the safe and stable operation of the power cable.

附图说明Description of drawings

图1为本发明方法实施例的流程示意图;Fig. 1 is the schematic flow sheet of the method embodiment of the present invention;

图2为本发明三芯电缆稳态热路模型示意图;Fig. 2 is a schematic diagram of a three-core cable steady-state thermal circuit model of the present invention;

图3为本发明实验测量10kV三芯电缆达到稳态时线芯与表皮温度实验值;Fig. 3 is that the present invention's experimental measurement 10kV three-core cable reaches steady state when wire core and skin temperature experiment value;

图4为本发明装置实施例的结构示意图。Fig. 4 is a schematic structural diagram of an embodiment of the device of the present invention.

具体实施方式Detailed ways

下面结合附图对本发明环境热阻影响三芯电缆线芯温度的评估方法的具体实施方式做详细描述。The specific implementation of the method for evaluating the influence of environmental thermal resistance on the core temperature of a three-core cable according to the present invention will be described in detail below in conjunction with the accompanying drawings.

如图1所示,一种环境热阻影响三芯电缆线芯温度的评估方法,包括步骤:As shown in Figure 1, an evaluation method for the influence of environmental thermal resistance on the core temperature of a three-core cable includes steps:

S110、根据三芯电缆的热路模型,得到空气敷设下的环境热阻和/或土壤敷设下的环境热阻;S110, according to the thermal circuit model of the three-core cable, obtain the environmental thermal resistance under air laying and/or the environmental thermal resistance under soil laying;

S120、根据三芯电缆的热路模型,得到三芯电缆的线芯温度;S120. Obtain the core temperature of the three-core cable according to the thermal circuit model of the three-core cable;

S130、若三芯电缆为空气敷设,根据空气敷设下的环境热阻与环境温度的关系以及确定线芯温度对空气敷设下的环境热阻的灵敏度;S130. If the three-core cable is laid by air, according to the relationship between the ambient thermal resistance and the ambient temperature under air laying and Determine the sensitivity of the wire core temperature to the ambient thermal resistance under air laying;

S140、若三芯电缆为土壤敷设,根据确定线芯温度对土壤敷设下的环境热阻的灵敏度;S140. If the three-core cable is laid in soil, according to Determine the sensitivity of the wire core temperature to the ambient thermal resistance under soil laying;

其中表示线芯温度对空气敷设下的环境热阻的灵敏度或线芯温度对土壤敷设下的环境热阻的灵敏度,θ1表示线芯温度,T4表示空气敷设下的环境热阻或土壤敷设下的环境热阻。in Indicates the sensitivity of the core temperature to the environmental thermal resistance under air laying or the sensitivity of the core temperature to the environmental thermal resistance under soil laying, θ 1 represents the core temperature, T 4 represents the environmental thermal resistance under air laying or soil laying ambient thermal resistance.

本发明的三芯电缆可以为10kV(千伏)的三芯电缆等。如图2所示,为三芯电缆稳态热路模型示意图,在三芯电缆的热路模型中,根据IEC60287可知:The three-core cable of the present invention may be a 10kV (kilovolt) three-core cable or the like. As shown in Figure 2, it is a schematic diagram of the steady-state thermal circuit model of a three-core cable. In the thermal circuit model of a three-core cable, according to IEC60287, it can be known that:

当为空气敷设时,环境热阻T4为:When laying in air, the ambient thermal resistance T4 is:

TT 44 == 11 ππ ·&Center Dot; DD. ee ·· hh ·· (( ΔθΔθ SS )) 11 // 44 -- -- -- (( 11 ))

其中式(1)中的π表示圆周率;De表示三芯电缆外径,单位可以是m(米);h表示传热系数;Δθs表示三芯电缆表皮温升,单位是K(开尔文)。Among them, π in formula (1) represents the circumference ratio; D e represents the outer diameter of the three-core cable, and the unit can be m (meter); h represents the heat transfer coefficient; Δθ s represents the temperature rise of the three-core cable skin, and the unit is K (Kelvin) .

当为土壤敷设时,环境热阻T4为:When laying in soil, the ambient thermal resistance T 4 is:

TT 44 == ρρ TT 22 ππ lnln (( uu ++ uu 22 -- 11 )) -- -- -- (( 22 ))

其中式(2)中的π表示圆周率;ρT表示土壤热阻系数,单位可以是K·m/W(开尔文·米/瓦);L表示三芯电缆轴线到地表的距离,单位可以是mm(毫米);De表示三芯电缆外径,单位可以是mm;ln表示对数函数。Among them, π in formula (2) represents the circumference ratio; ρ T represents the thermal resistivity of the soil, and the unit can be K m/W (Kelvin m/watt); L represents the distance from the axis of the three-core cable to the ground surface, and the unit can be mm (mm); D e represents the outer diameter of the three-core cable, and the unit can be mm; ln represents a logarithmic function.

比拟电路中的节点电压法,根据图2列温差平衡方程:Compared with the node voltage method in the circuit, the temperature difference balance equation is listed according to Figure 2:

θ12=T1/3×(3I2R+3Qd/2)        (3)θ 12 =T 1 /3×(3I 2 R+3Q d /2) (3)

θ23=T2×[3Qd+3(1+λ1)I2R]       (4)θ 23 =T 2 ×[3Q d +3(1+λ 1 )I 2 R] (4)

θ34=T3×[3Qd+3(1+λ12)I2R]   (5)θ 34 =T 3 ×[3Q d +3(1+λ 12 )I 2 R] (5)

θ40=T4×[3Qd+3(1+λ12)I2R]   (6)θ 40 =T 4 ×[3Q d +3(1+λ 12 )I 2 R] (6)

将公式(3)、公式(4)、公式(5)、公式(6)相加,得到三芯电缆的线芯温度为:Adding formula (3), formula (4), formula (5) and formula (6), the core temperature of the three-core cable is obtained as:

θ1=θ0+T1(I2R+Qd/2)+3T2[I2R(1+λ1)+Qd]+3(T3+T4)[I2R(1+λ12)+Qd]  (7)θ 1 =θ 0 +T 1 (I 2 R+Q d /2)+3T 2 [I 2 R(1+λ 1 )+Q d ]+3(T 3 +T 4 )[I 2 R(1 +λ 12 )+Q d ] (7)

其中公式(7)中的θ1为三芯电缆的线芯温度;θ2为绝缘外表面及金属屏蔽层温度;θ3为铠装层温度;θ4为电缆外护套表面温度;θ0为环境温度;T1为单个线芯绝缘层热阻;I为三芯电缆的载流量;R为线芯交流电阻;Qc=I2R,为单个线芯电缆线芯及内屏蔽层产生的损耗;Qd为单个线芯绝缘及绝缘屏蔽层的介质损耗;T2为填充层及内护套热阻,λ1为单个线芯金属套及屏蔽的损耗因素,T3为外护套热阻,T4为环境热阻,λ2为单个线芯铠装层的损耗因素。θ 1 in formula (7) is the core temperature of the three-core cable; θ 2 is the temperature of the outer surface of the insulation and the metal shielding layer; θ 3 is the temperature of the armor layer; θ 4 is the surface temperature of the cable outer sheath; θ 0 is the ambient temperature; T 1 is the thermal resistance of the insulation layer of a single core; I is the current carrying capacity of the three-core cable; R is the AC resistance of the core; Q d is the dielectric loss of a single core insulation and insulating shielding layer; T 2 is the thermal resistance of the filling layer and the inner sheath, λ 1 is the loss factor of a single core metal sheath and shielding, T 3 is the outer sheath Thermal resistance, T 4 is the thermal resistance of the environment, λ 2 is the loss factor of a single core armor layer.

表示线芯温度θ1对环境热阻T4的灵敏度,T4为自变量参数,θ1为因变量参数。根据步骤S110和步骤S120得到的数据,根据即可以分析环境热阻对线芯温度的影响程度。由于空气敷设和土壤敷设情况不同,所以下面分两种情况对环境热阻对线芯温度的影响程度进行说明。 Indicates the sensitivity of core temperature θ 1 to ambient thermal resistance T 4 , T 4 is the independent variable parameter, θ 1 is the dependent variable parameter. According to the data obtained in step S110 and step S120, according to That is, the degree of influence of the ambient thermal resistance on the core temperature can be analyzed. Since the conditions of air laying and soil laying are different, the following two situations will be used to illustrate the influence of ambient thermal resistance on the core temperature.

(1)当为空气敷设时:(1) When laying by air:

由于环境热阻T4与环境温度θ0有关,只考虑环境热阻对线芯温度的影响是不准确的,因此要考虑两个因素的影响。因此得到线芯温度θ1对环境热阻T4的归一化灵敏度为:Since the ambient thermal resistance T 4 is related to the ambient temperature θ 0 , it is inaccurate to only consider the influence of the ambient thermal resistance on the core temperature, so the influence of two factors should be considered. Therefore, the normalized sensitivity of the core temperature θ 1 to the ambient thermal resistance T 4 is obtained as:

SS TT 44 θθ 11 == {{ 44 ππ DD. ee hh (( ΔΔ θθ SS )) 55 44 ++ 33 [[ (( 11 ++ λλ 11 ++ λλ 22 )) II 22 RR ++ QQ dd ]] }} ·&Center Dot; TT 44 θθ 11 -- -- -- (( 88 ))

(2)当为土壤敷设时:(2) When laying for soil:

由于土壤的环境热阻较大,环境温度基本保持不变,所以可以忽略环境温度的微小变化,仅考虑环境热阻对线芯温度的影响。得到土壤敷设时线芯温度对环境热阻的归一化灵敏度为:Due to the large environmental thermal resistance of the soil, the ambient temperature remains basically unchanged, so the slight change in the ambient temperature can be ignored, and only the influence of the environmental thermal resistance on the core temperature is considered. The normalized sensitivity of the wire core temperature to the ambient thermal resistance when the soil is laid is obtained as:

SS TT 44 θθ 11 == 33 [[ (( 11 ++ λλ 11 ++ λλ 22 )) II 22 RR ++ QQ dd ]] ·&Center Dot; TT 44 θθ 11 -- -- -- (( 99 ))

根据公式(8)、公式(9)可得到不同敷设情况下,加载电流为不同数值时,线芯温度对环境热阻的灵敏度,其中部分数据如下表1所示。According to the formula (8) and formula (9), the sensitivity of the wire core temperature to the ambient thermal resistance can be obtained under different laying conditions and when the loading current is different values. Some of the data are shown in Table 1 below.

表1两种不同敷设情况下线芯温度对环境热阻的灵敏度Table 1 Sensitivity of wire core temperature to ambient thermal resistance under two different laying conditions

参数灵敏度分级如下表2所示:The parameter sensitivity classification is shown in Table 2 below:

表2参数灵敏度分级Table 2 Parameter sensitivity classification

根据上述表1和表2可知,在空气敷设情况下:加载电流为200A时,为中等灵敏;加载电流为300A、400A、500A时,为灵敏,且500A时的灵敏度最高。在土壤敷设情况下:加载不同电流时为不灵敏。According to the above Table 1 and Table 2, in the case of air laying: when the loading current is 200A, It is moderately sensitive; when the loading current is 300A, 400A, 500A, The most sensitive, and the highest sensitivity at 500A. In the case of soil laying: when loaded with different currents as insensitive.

实验测量10kV三芯电缆达到稳态时线芯与表皮温度实验值如图3所示。图3中的a表示空气敷设和土壤敷设的线芯温度差值,图3中的b表示空气敷设和土壤敷设的表皮温度差值。结合表1和图3中的数据可知:在同一敷设情况下,随着加载电流的增大,线芯温度对外部环境热阻的灵敏度越来越大。同时也证明本发明对于确定环境热阻对三芯电缆线芯温度的影响程度具有有效性。另外,根据上述分析可知,在加载电流较大时,尤其是空气敷设情况下,需要加大环境温度的监测力度,从而防止线芯温度过高,保证电力线缆的安全稳定运行。The experimental values of the core and skin temperature when the 10kV three-core cable reaches a steady state are shown in Figure 3. A in Figure 3 represents the core temperature difference between air laying and soil laying, and b in Figure 3 represents the skin temperature difference between air laying and soil laying. Combining the data in Table 1 and Figure 3, it can be seen that under the same laying condition, as the loading current increases, the sensitivity of the core temperature to the thermal resistance of the external environment becomes larger and larger. At the same time, it also proves that the invention is effective for determining the degree of influence of environmental thermal resistance on the core temperature of a three-core cable. In addition, according to the above analysis, when the loading current is large, especially in the case of air laying, it is necessary to increase the monitoring of the ambient temperature to prevent the core temperature from being too high and ensure the safe and stable operation of the power cable.

基于同一发明构思,本发明还提供一种环境热阻影响三芯电缆线芯温度的评估装置,下面结合附图对本发明装置的具体实施方式做详细描述。Based on the same inventive concept, the present invention also provides a device for evaluating the influence of environmental thermal resistance on the core temperature of a three-core cable. The specific implementation of the device of the present invention will be described in detail below with reference to the accompanying drawings.

如图4所示,一种环境热阻影响三芯电缆线芯温度的评估装置,包括:As shown in Figure 4, an evaluation device for the influence of environmental thermal resistance on the core temperature of a three-core cable includes:

环境热阻确定模块410,用于根据三芯电缆的热路模型,得到空气敷设下的环境热阻和/或土壤敷设下的环境热阻;The environmental thermal resistance determination module 410 is used to obtain the environmental thermal resistance under air laying and/or the environmental thermal resistance under soil laying according to the thermal circuit model of the three-core cable;

线芯温度确定模块420,用于根据三芯电缆的热路模型,得到三芯电缆的线芯温度;The wire core temperature determination module 420 is used to obtain the wire core temperature of the three-core cable according to the thermal circuit model of the three-core cable;

第一灵敏度确定模块430,用于在三芯电缆为空气敷设时,根据空气敷设下的环境热阻与环境温度的关系以及确定线芯温度对空气敷设下的环境热阻的灵敏度;The first sensitivity determination module 430 is used for when the three-core cable is laid in air, according to the relationship between the ambient thermal resistance and the ambient temperature under air laying and Determine the sensitivity of the wire core temperature to the ambient thermal resistance under air laying;

第二灵敏度确定模块440,用于在三芯电缆为土壤敷设时,根据确定线芯温度对土壤敷设下的环境热阻的灵敏度;The second sensitivity determination module 440 is used for when the three-core cable is laid in soil, according to Determine the sensitivity of the wire core temperature to the ambient thermal resistance under soil laying;

其中表示线芯温度对空气敷设下的环境热阻的灵敏度或线芯温度对土壤敷设下的环境热阻的灵敏度,θ1表示线芯温度,T4表示空气敷设下的环境热阻或土壤敷设下的环境热阻。in Indicates the sensitivity of the core temperature to the environmental thermal resistance under air laying or the sensitivity of the core temperature to the environmental thermal resistance under soil laying, θ 1 represents the core temperature, T 4 represents the environmental thermal resistance under air laying or soil laying ambient thermal resistance.

根据如图2所示的三芯电缆稳态热路模型示意图,可知空气敷设下的环境热阻其中De表示三芯电缆外径,h表示传热系数,Δθs表示三芯电缆表皮温升;土壤敷设下的环境热阻其中ρT表示土壤热阻系数,L表示三芯电缆轴线到地表的距离,De表示三芯电缆外径。三芯电缆的线芯温度θ1=θ0+T1(I2R+Qd/2)+3T2[I2R(1+λ1)+Qd]+3(T3+T4)[I2R(1+λ12)+Qd],其中θ1为三芯电缆的线芯温度,θ0为环境温度,T1为单个线芯绝缘层热阻,I为三芯电缆的载流量,R为线芯交流电阻,Qd为单个线芯绝缘及绝缘屏蔽层的介质损耗,T2为填充层及内护套热阻,λ1为单个线芯金属套及屏蔽的损耗因素,T3为外护套热阻,T4为环境热阻,λ2为单个线芯铠装层的损耗因素。According to the schematic diagram of the steady-state thermal circuit model of the three-core cable shown in Figure 2, it can be known that the ambient thermal resistance under air laying Where D e represents the outer diameter of the three-core cable, h represents the heat transfer coefficient, Δθ s represents the temperature rise of the three-core cable skin; the environmental thermal resistance under the soil laying where ρT is the soil thermal resistivity coefficient, L represents the distance from the axis of the three-core cable to the ground surface, and D e represents the outer diameter of the three-core cable. Core temperature of three-core cable θ 1 =θ 0 +T 1 (I 2 R+Q d /2)+3T 2 [I 2 R(1+λ 1 )+Q d ]+3(T 3 +T 4 )[I 2 R(1+λ 12 )+Q d ], where θ 1 is the core temperature of the three-core cable, θ 0 is the ambient temperature, T 1 is the thermal resistance of the insulation layer of a single core, and I is The ampacity of the three-core cable, R is the AC resistance of the core, Q d is the dielectric loss of the insulation and insulation shielding layer of a single core, T 2 is the thermal resistance of the filling layer and the inner sheath, λ 1 is the metal sheath of a single core and The loss factor of shielding, T 3 is the thermal resistance of the outer sheath, T 4 is the thermal resistance of the environment, and λ 2 is the loss factor of a single core armor layer.

根据环境热阻确定模块410和线芯温度确定模块420得到的数据,第一灵敏度确定模块430或第二灵敏度确定模块440即可以根据分析环境热阻对线芯温度的影响程度。当为空气敷设时:由于环境热阻T4与环境温度θ0有关,第一灵敏度确定模块430要考虑两个因素的影响,因此得到线芯温度θ1对环境热阻T4的归一化灵敏度为: S T 4 θ 1 = { 4 π D e h ( Δ θ S ) 5 4 + 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] } · T 4 θ 1 . 当为土壤敷设时:由于土壤的环境热阻较大,环境温度基本保持不变,所以第二灵敏度确定模块440可以忽略环境温度的微小变化,仅考虑环境热阻对线芯温度的影响,得到土壤敷设时线芯温度对环境热阻的归一化灵敏度为: S T 4 θ 1 = 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] · T 4 θ 1 . According to the data obtained by the ambient thermal resistance determination module 410 and the core temperature determination module 420, the first sensitivity determination module 430 or the second sensitivity determination module 440 can be based on Analyze the influence of ambient thermal resistance on the core temperature. When laying air: because the ambient thermal resistance T4 is related to the ambient temperature θ0 , the first sensitivity determination module 430 will consider the influence of two factors, so the normalization of the core temperature θ1 to the ambient thermal resistance T4 is obtained The sensitivity is: S T 4 θ 1 = { 4 π D. e h ( Δ θ S ) 5 4 + 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] } · T 4 θ 1 . When laying in soil: because the ambient thermal resistance of the soil is relatively large, the ambient temperature remains basically unchanged, so the second sensitivity determination module 440 can ignore the small changes in the ambient temperature, and only consider the influence of the ambient thermal resistance on the core temperature. The normalized sensitivity of core temperature to ambient thermal resistance when laying in soil is: S T 4 θ 1 = 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] &Center Dot; T 4 θ 1 .

根据第一灵敏度确定模块430得到的灵敏度公式和第二灵敏度确定模块440得到的灵敏度公式,可以得到不同加载电流下不同敷设时环境热阻对线芯温度的影响程度,即随着加载电流的增大,线芯温度对外部环境热阻的灵敏度越来越大,所以在三芯电缆加载电流较大时,尤其是三芯电缆的敷设为空气辐射时,应加大环境温度的监测力度,从而保证电力线缆的安全稳定运行。According to the sensitivity formula obtained by the first sensitivity determination module 430 and the sensitivity formula obtained by the second sensitivity determination module 440, the degree of influence of the environmental thermal resistance on the wire core temperature during different laying under different loading currents can be obtained, that is, with the increase of the loading current The sensitivity of the core temperature to the thermal resistance of the external environment is increasing, so when the three-core cable is loaded with a large current, especially when the laying of the three-core cable is air radiation, the monitoring of the ambient temperature should be strengthened, so that Ensure the safe and stable operation of power cables.

本发明装置其它技术特征与本发明方法相同,在此不予赘述。Other technical features of the device of the present invention are the same as those of the method of the present invention, and will not be repeated here.

以上所述实施例的各技术特征可以进行任意的组合,为使描述简洁,未对上述实施例中的各个技术特征所有可能的组合都进行描述,然而,只要这些技术特征的组合不存在矛盾,都应当认为是本说明书记载的范围。The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

以上所述实施例仅表达了本发明的几种实施方式,其描述较为具体和详细,但并不能因此而理解为对发明专利范围的限制。应当指出的是,对于本领域的普通技术人员来说,在不脱离本发明构思的前提下,还可以做出若干变形和改进,这些都属于本发明的保护范围。因此,本发明专利的保护范围应以所附权利要求为准。The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1.一种环境热阻影响三芯电缆线芯温度的评估方法,其特征在于,包括步骤:1. A method for assessing the impact of environmental thermal resistance on the core temperature of a three-core cable, characterized in that it comprises steps: 根据三芯电缆的热路模型,得到空气敷设下的环境热阻和/或土壤敷设下的环境热阻;According to the thermal circuit model of the three-core cable, the environmental thermal resistance under air laying and/or the environmental thermal resistance under soil laying is obtained; 根据三芯电缆的热路模型,得到三芯电缆的线芯温度;According to the thermal circuit model of the three-core cable, the core temperature of the three-core cable is obtained; 若三芯电缆为空气敷设,根据空气敷设下的环境热阻与环境温度的关系以及确定线芯温度对空气敷设下的环境热阻的灵敏度;If the three-core cable is laid by air, according to the relationship between the ambient thermal resistance and the ambient temperature under air laying and Determine the sensitivity of the wire core temperature to the ambient thermal resistance under air laying; 若三芯电缆为土壤敷设,根据确定线芯温度对土壤敷设下的境热阻的灵敏度;If the three-core cable is laid in soil, according to Determine the sensitivity of wire core temperature to environmental thermal resistance under soil laying; 其中表示线芯温度对空气敷设下的环境热阻的灵敏度或线芯温度对土壤敷设下的环境热阻的灵敏度,θ1表示线芯温度,T4表示空气敷设下的环境热阻或土壤敷设下的环境热阻。in Indicates the sensitivity of the core temperature to the environmental thermal resistance under air laying or the sensitivity of the core temperature to the environmental thermal resistance under soil laying, θ 1 represents the core temperature, T 4 represents the environmental thermal resistance under air laying or soil laying ambient thermal resistance. 2.根据权利要求1所述的环境热阻影响三芯电缆线芯温度的评估方法,其特征在于,空气敷设下的环境热阻其中De表示三芯电缆外径,h表示传热系数,Δθs表示三芯电缆表皮温升;土壤敷设下的环境热阻其中ρT表示土壤热阻系数,L表示三芯电缆轴线到地表的距离,De表示三芯电缆外径。2. the environmental thermal resistance according to claim 1 influences the assessment method of three-core cable core temperature, it is characterized in that the environmental thermal resistance under air laying Where D e represents the outer diameter of the three-core cable, h represents the heat transfer coefficient, Δθ s represents the temperature rise of the three-core cable skin; the environmental thermal resistance under the soil laying where ρT is the soil thermal resistivity coefficient, L represents the distance from the axis of the three-core cable to the ground surface, and D e represents the outer diameter of the three-core cable. 3.根据权利要求2所述的环境热阻影响三芯电缆线芯温度的评估方法,其特征在于,三芯电缆的线芯温度θ1=θ0+T1(I2R+Qd/2)+3T2[I2R(1+λ1)+Qd]+3(T3+T4)[I2R(1+λ12)+Qd],其中θ1为三芯电缆的线芯温度,θ0为环境温度,T1为单个线芯绝缘层热阻,I为三芯电缆的载流量,R为线芯交流电阻,Qd为单个线芯绝缘及绝缘屏蔽层的介质损耗,T2为填充层及内护套热阻,λ1为单个线芯金属套及屏蔽的损耗因素,T3为外护套热阻,T4为环境热阻,λ2为单个线芯铠装层的损耗因素。3. The method for assessing the impact of environmental thermal resistance on the core temperature of a three-core cable according to claim 2, wherein the core temperature of the three-core cable θ 10 +T 1 (I 2 R+Q d / 2)+3T 2 [I 2 R(1+λ 1 )+Q d ]+3(T 3 +T 4 )[I 2 R(1+λ 12 )+Q d ], where θ 1 is The core temperature of the three-core cable, θ 0 is the ambient temperature, T 1 is the thermal resistance of the insulation layer of a single core, I is the current carrying capacity of the three-core cable, R is the AC resistance of the core, and Q d is the insulation and insulation of a single core The dielectric loss of the shielding layer, T 2 is the thermal resistance of the filling layer and the inner sheath, λ 1 is the loss factor of a single core metal sheath and shielding, T 3 is the thermal resistance of the outer sheath, T 4 is the thermal resistance of the environment, λ 2 is the loss factor of a single core armor layer. 4.根据权利要求3所述的环境热阻影响三芯电缆线芯温度的评估方法,其特征在于,线芯温度对空气敷设下的环境热阻的灵敏度 S T 4 θ 1 = { 4 π D e h ( Δθ S ) 5 4 + 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] } · T 4 θ 1 . 4. the evaluation method that environmental thermal resistance affects three-core cable core temperature according to claim 3, is characterized in that, the sensitivity of core temperature to the environmental thermal resistance under air laying S T 4 θ 1 = { 4 π D. e h ( Δθ S ) 5 4 + 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] } &Center Dot; T 4 θ 1 . 5.根据权利要求3所述的环境热阻影响三芯电缆线芯温度的评估方法,其特征在于,线芯温度对土壤敷设下的环境热阻的灵敏度 S T 4 θ 1 = 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] · T 4 θ 1 . 5. the evaluation method that environmental thermal resistance affects three-core cable core temperature according to claim 3, is characterized in that, the sensitivity of core temperature to the environmental thermal resistance under soil laying S T 4 θ 1 = 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] &Center Dot; T 4 θ 1 . 6.一种环境热阻影响三芯电缆线芯温度的评估装置,其特征在于,包括:6. An evaluation device for the influence of environmental thermal resistance on the core temperature of a three-core cable, characterized in that it comprises: 环境热阻确定模块,用于根据三芯电缆的热路模型,得到空气敷设下的环境热阻和/或土壤敷设下的环境热阻;The environmental thermal resistance determination module is used to obtain the environmental thermal resistance under air laying and/or the environmental thermal resistance under soil laying according to the thermal circuit model of the three-core cable; 线芯温度确定模块,用于根据三芯电缆的热路模型,得到三芯电缆的线芯温度;The wire core temperature determination module is used to obtain the wire core temperature of the three-core cable according to the thermal circuit model of the three-core cable; 第一灵敏度确定模块,用于在三芯电缆为空气敷设时,根据空气敷设下的环境热阻与环境温度的关系以及确定线芯温度对空气敷设下的环境热阻的灵敏度;The first sensitivity determination module is used for when the three-core cable is laid in air, according to the relationship between the ambient thermal resistance and the ambient temperature under air laying and Determine the sensitivity of the wire core temperature to the ambient thermal resistance under air laying; 第二灵敏度确定模块,用于在三芯电缆为土壤敷设时,根据确定线芯温度对土壤敷设下的环境热阻的灵敏度;The second sensitivity determination module is used for when the three-core cable is laid in soil, according to Determine the sensitivity of the wire core temperature to the ambient thermal resistance under soil laying; 其中表示线芯温度对空气敷设下的环境热阻的灵敏度或线芯温度对土壤敷设下的环境热阻的灵敏度,θ1表示线芯温度,T4表示空气敷设下的环境热阻或土壤敷设下的环境热阻。in Indicates the sensitivity of the core temperature to the environmental thermal resistance under air laying or the sensitivity of the core temperature to the environmental thermal resistance under soil laying, θ 1 represents the core temperature, T 4 represents the environmental thermal resistance under air laying or soil laying ambient thermal resistance. 7.根据权利要求6所述的环境热阻影响三芯电缆线芯温度的评估装置,其特征在于,空气敷设下的环境热阻其中De表示三芯电缆外径,h表示传热系数,Δθs表示三芯电缆表皮温升;土壤敷设下的环境热阻其中ρT表示土壤热阻系数,L表示三芯电缆轴线到地表的距离,De表示三芯电缆外径。7. the evaluation device that environmental thermal resistance affects three-core cable core temperature according to claim 6, is characterized in that the environmental thermal resistance under air laying Where D e represents the outer diameter of the three-core cable, h represents the heat transfer coefficient, Δθ s represents the temperature rise of the three-core cable skin; the environmental thermal resistance under the soil laying where ρT is the soil thermal resistivity coefficient, L represents the distance from the axis of the three-core cable to the ground surface, and D e represents the outer diameter of the three-core cable. 8.根据权利要求7所述的环境热阻影响三芯电缆线芯温度的评估装置,其特征在于,三芯电缆的线芯温度θ1=θ0+T1(I2R+Qd/2)+3T2[I2R(1+λ1)+Qd]+3(T3+T4)[I2R(1+λ12)+Qd],其中θ1为三芯电缆的线芯温度,θ0为环境温度,T1为单个线芯绝缘层热阻,I为三芯电缆的载流量,R为线芯交流电阻,Qd为单个线芯绝缘及绝缘屏蔽层的介质损耗,T2为填充层及内护套热阻,λ1为单个线芯金属套及屏蔽的损耗因素,T3为外护套热阻,T4为环境热阻,λ2为单个线芯铠装层的损耗因素。8. The evaluation device for the influence of environmental thermal resistance on the core temperature of a three-core cable according to claim 7, wherein the core temperature of the three-core cable is θ 10 +T 1 (I 2 R+Q d / 2)+3T 2 [I 2 R(1+λ 1 )+Q d ]+3(T 3 +T 4 )[I 2 R(1+λ 12 )+Q d ], where θ 1 is The core temperature of the three-core cable, θ 0 is the ambient temperature, T 1 is the thermal resistance of the insulation layer of a single core, I is the current carrying capacity of the three-core cable, R is the AC resistance of the core, and Q d is the insulation and insulation of a single core The dielectric loss of the shielding layer, T 2 is the thermal resistance of the filling layer and the inner sheath, λ 1 is the loss factor of a single core metal sheath and shielding, T 3 is the thermal resistance of the outer sheath, T 4 is the thermal resistance of the environment, λ 2 is the loss factor of a single core armor layer. 9.根据权利要求8所述的环境热阻影响三芯电缆线芯温度的评估装置,其特征在于,线芯温度对空气敷设下的环境热阻的灵敏度 S T 4 θ 1 = { 4 π D e h ( Δθ S ) 5 4 + 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] } · T 4 θ 1 . 9. the evaluation device that environmental thermal resistance affects three-core cable core temperature according to claim 8, is characterized in that, the sensitivity of core temperature to the environmental thermal resistance under air laying S T 4 θ 1 = { 4 π D. e h ( Δθ S ) 5 4 + 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] } &Center Dot; T 4 θ 1 . 10.根据权利要求8所述的环境热阻影响三芯电缆线芯温度的评估装置,其特征在于,线芯温度对土壤敷设下的环境热阻的灵敏度 S T 4 θ 1 = 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] · T 4 θ 1 . 10. The evaluation device that environmental thermal resistance affects the core temperature of a three-core cable according to claim 8, characterized in that the sensitivity of the core temperature to the environmental thermal resistance under soil laying S T 4 θ 1 = 3 [ ( 1 + λ 1 + λ 2 ) I 2 R + Q d ] · T 4 θ 1 .
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