A cable layout method for bridge cranes based on the space envelope method of current-carrying rate

Abstract

The present invention discloses a cable tray layout method based on the current-carrying rate spatial envelope method, comprising determining the cross-sectional area of the cable to be installed on the cable tray, determining the thickness of the cable's insulation layer, determining the radius of the cable's heat dissipation gap, calculating the cable radius, repeating the previous steps to obtain cables with different given current-carrying rates and corresponding heat dissipation gap radii to be installed on the tray, expanding the heat dissipation gap radius of each cable to form a new heat dissipation gap radius, and dividing the cables into k layers and arranging them in intervals from left to right and from bottom to top, all following the principle of heat dissipation compensation radius from large to small. The present invention can achieve an optimal cable arrangement, so that the cables have excellent heat dissipation performance, reduce the overall space occupied, and adapt to the different current carrying capacities of the cables.

Description

Technical Field

[0001] The present invention relates to a cable layout method, in particular to a cable layout arrangement method based on current carrying rate. Background Art

[0002] Cables and equipment, pipelines, ventilation, electrical, instrumentation and other disciplines must share a limited space, resulting in a complex spatial arrangement of cable trays. Currently, there is no universal cable layout method, which brings great difficulties to the cable laying work. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a bridge cable layout method based on the current-carrying rate spatial envelope method with excellent heat dissipation performance to ensure the safe use of cables.

[0004] In order to achieve the above object, the technical solution adopted in the present invention is:

[0005] A bridge cable layout method based on the current-carrying rate spatial envelope method of the present invention comprises the following steps:

[0006] The first step is to determine the cross-sectional area of a cable to be installed on the cable tray. The specific process is as follows:

[0007] According to the number of cores of a cable to be installed on the bridge and a given current-carrying rate I, a minimum standard current-carrying rate greater than the given current-carrying rate I is obtained, and then a cross-sectional area S of the cable corresponding to the minimum standard current-carrying rate is obtained;

[0008] Step 2: Determine the insulation thickness Δ of a cable:

[0009]

[0010]

[0011] U m =1.15IR

[0012] r c is the outer radius of a cable conductor layer, Δ is the thickness of a cable insulation layer; E m is the partial discharge withstand field strength; U m is the maximum operating voltage of the cable; I is the given current carrying rate, R is the cable resistance, and S is the cross-sectional area of the cable selected in the first step;

[0013] Step 3: Determine the radius R of the heat dissipation gap of the cable. The center of the circle with radius R is the center of the cable cross section:

[0014] R=Δ+2.5r c

[0015] rc is the outer radius of the cable conductor layer;

[0016] Step 4: Calculate the radius r of the cable;

[0017] r=r c +Δ

[0018] Step 5: Repeat steps 1 to 4 to obtain the current carrying capacity I to be installed on the bridge and having different i The corresponding heat dissipation gap radius is recorded as R i The radius of the cable is r i ;

[0019] Step 6: Set the heat dissipation gap radius R of each cable i Expanded to R i ′, forming a new heat dissipation gap radius, that is, converting the blocked heat dissipation area into the expanded heat dissipation gap;

[0020]

[0021] Among them, the occlusion half angle

[0022] r i represents the radius of cable i;

[0023] R i is the radius of the heat dissipation gap of cable i;

[0024] Step 7: Divide the cables into k layers and arrange them in intervals from left to right and from bottom to top, following the principle of large to small heat dissipation compensation radius. Let m be the serial number of the leftmost cable in the i-th layer, and n be the serial number of the rightmost cable in the i-th layer. At the same time, ensure that the compensation heat dissipation gaps of adjacent cables are tangentially arranged on the bridge.

[0025] The total horizontal length L of the cables in each layer can be i Perform appropriate amplification, namely:

[0026]

[0027] m is the number of the leftmost cable in the i-th layer, n is the number of the rightmost cable in the i-th layer, R ′ ij is the heat dissipation compensation radius of the jth cable in the i-th layer;

[0028] The length L of the bridge is: L=max{L1, L2...L k}, k is the maximum number of layers;

[0029] The height H of the bridge is:

[0030] k is the number of layers of the bridge; R ′ im is the heat dissipation gap radius of the leftmost cable in the i-th layer; r im is the radius of the leftmost cable in the i-th layer, i.e. the maximum cable radius; m is the serial number of the leftmost cable in the i-th layer.

[0031] The beneficial effects of the present invention are:

[0032] The present invention can achieve optimal arrangement of cables, so that the cables have excellent heat dissipation performance, reduce the overall space occupied, and can adapt to different current carrying capacities of the cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A cross-sectional arrangement diagram of a bridge using the bridge cable layout method based on the current carrying capacity spatial envelope method of the present invention;

[0034] Figure 2 This is the heat dissipation gap compensation diagram;

[0035] Figure 3 The present invention is a flow chart of the cable tray layout method based on the current-carrying rate spatial envelope method. DETAILED DESCRIPTION

[0036] The following combination Figure 1 , Figure 2 , Figure 3 The specific implementation methods of the present invention are further described.

[0037] As attached Figure 3 As shown, a bridge cable layout method based on the current carrying rate spatial envelope method of the present invention includes the following steps:

[0038] The first step is to determine the cross-sectional area of a cable to be installed on the cable tray. The specific process is as follows:

[0039] According to the number of cores of a cable to be installed on the bridge and the given current-carrying rate I, the minimum standard current-carrying rate greater than the given current-carrying rate I is obtained, and then the cross-sectional area S of the cable corresponding to the minimum standard current-carrying rate is obtained (the cross-sectional area has standard specifications).

[0040] When selecting, look up the maximum current-carrying rate table corresponding to different cable cross-sectional areas (for details, see the reference [1] Xu Zhuyong, Sun Pingkui. Discussion on the selection method of cable cross-sectional area [J]. Electromechanical Technology, 2013, 36(05): 76-78. Table 1 on page 2). First, determine the column number based on the number of cores of the cable. Since the cable has a given current-carrying rate, there are some minimum standard current-carrying rate values in the column that are greater than the given current-carrying rate. The cross-sectional area corresponding to the minimum standard current-carrying rate value is the cross-sectional area of the cable being sought.

[0041] Step 2: Determine the insulation thickness Δ of a certain cable 4:

[0042]

[0043]

[0044] U m =1.15IR

[0045] r c is the outer radius of a cable conductor layer, Δ is the thickness of a cable insulation layer (mm); E m is the partial discharge withstand field strength, which is 15-24 (kV / mm); U m is the maximum operating voltage of the cable (V); I is the given current carrying rate, R is the cable resistance, and S is the cross-sectional area of the cable selected in the first step.

[0046] Step 3: Determine the radius R of the heat dissipation gap of the cable 4. The center of the circle with radius R is the center of the cable cross section.

[0047] R=r c +Δ+1.5r c =Δ+2.5r c

[0048] r c is the outer radius of the cable conductor layer.

[0049] Step 4: Calculate the radius r of the cable 4;

[0050] r=r c +Δ

[0051] r c is the outer radius of the conductor layer;

[0052] Step 5: Repeat steps 1 to 4 to obtain the current carrying capacity I to be installed on the bridge and having different i The corresponding heat dissipation gap radius is recorded as R i The radius of the cable is r i .

[0053] Step 6: Figure 2 As shown, the bottom of each cable 4 is in contact with the partition 2, and the heat dissipation area below the cable is blocked by the partition 2, resulting in a reduction in the reserved gap. Therefore, compensation is required, that is, the heat dissipation gap radius R of each cable is increased. i Expanded to R i ', thus forming a new heat dissipation gap radius 3. The blocked heat dissipation area is converted into the expanded heat dissipation gap.

[0054]

[0055] Among them, the occlusion half angle

[0056] r i represents the radius of cable i;

[0057] R i is the radius of the heat dissipation gap of cable i.

[0058] formula The derivation process is:

[0059] Blocked heat dissipation area S i for:

[0060]

[0061] Remaining area A i for:

[0062]

[0063] After compensation, the heat dissipation area S will be blocked i = Expanded gap area A ′ i -A i ,Right now:

[0064] A ′ i -A i =S i ,Right now

[0065]

[0066] The solution is:

[0067]

[0068] The heat dissipation gap radius R after compensation can be obtained i ′ .

[0069] Step 7: Figure 1 Arrange the cables in k layers, spaced apart from each other, from left to right and from bottom to top, following the principle of decreasing heat dissipation compensation radius. Let m be the number of the leftmost cable in layer i, and n be the number of the rightmost cable in layer i. Ensure that the compensation gaps between adjacent cables are tangential and arranged on the bridge.

[0070] Among them, because the compensation heat dissipation gaps of adjacent cables are tangent and the radius is not exactly the same, the tangent points are not on the same straight line, so the total horizontal length L of the cables in each layer can be calculated. i Perform appropriate amplification, namely:

[0071]

[0072] m is the number of the leftmost cable in the i-th layer, n is the number of the rightmost cable in the i-th layer, R ′ ij is the heat dissipation compensation radius of the jth cable in the i-th layer.

[0073] The length L of the bridge 1 is: L = max {L1, L2...L k}, k is the maximum number of layers.

[0074] The height H of bridge 1 is:

[0075] k is the number of layers of the bridge; R ′ im is the heat dissipation gap radius of the leftmost cable in the i-th layer; r im is the radius of the leftmost cable in the i-th layer, i.e. the maximum cable radius; m is the serial number of the leftmost cable in the i-th layer.

[0076] After completing the above steps, you can quickly complete the design of the cable tray and the spatial arrangement of the cables according to the current carrying capacity, while also ensuring the heat dissipation requirements of the cables.

Claims

1. A bridge cable layout method based on the current carrying capacity spatial envelope method, characterized in that The following steps are involved: The first step is to determine the cross-sectional area of a cable to be installed on the cable tray. The specific process is as follows: According to the number of cores of a cable to be installed on the bridge and a given current-carrying rate I, a minimum standard current-carrying rate greater than the given current-carrying rate I is obtained, and then a cross-sectional area S of the cable corresponding to the minimum standard current-carrying rate is obtained; Step 2: Determine the insulation thickness Δ of a cable: U m =1.15IR r c is the outer radius of a cable conductor layer, Δ is the thickness of a cable insulation layer; E m is the partial discharge withstand field strength; U m is the maximum operating voltage of the cable; I is the given current carrying rate, R is the cable resistance, and S is the cross-sectional area of the cable selected in the first step; Step 3: Determine the radius R of the heat dissipation gap of the cable. The center of the circle with radius R is the center of the cable cross section: R=Δ+2.5r c r c is the outer radius of the cable conductor layer; Step 4: Calculate the radius r of the cable; r=r c +D Step 5: Repeat steps 1 to 4 to obtain the current carrying capacity I to be installed on the bridge and having different i The corresponding heat dissipation gap radius is recorded as R i The radius of the cable is r i ; Step 6: Set the heat dissipation gap radius R of each cable i Expanded to R i ′, forming a new heat dissipation gap radius, that is, converting the blocked heat dissipation area into the expanded heat dissipation gap; Among them, the occlusion half angle r i represents the radius of cable i; R i is the radius of the heat dissipation gap of cable i; Step 7: Divide the cables into k layers and arrange them in intervals from left to right and from bottom to top, following the principle of large to small heat dissipation compensation radius. Let m be the serial number of the leftmost cable in the i-th layer, and n be the serial number of the rightmost cable in the i-th layer. At the same time, ensure that the compensation heat dissipation gaps of adjacent cables are tangentially arranged on the bridge. The total horizontal length L of the cables in each layer can be i Perform appropriate amplification, namely: m is the number of the leftmost cable in the i-th layer, n is the number of the rightmost cable in the i-th layer, R′ ij is the heat dissipation compensation radius of the jth cable in the i-th layer; The length L of the bridge is: L=max{L1, L2...L k }, k is the maximum number of layers; The height H of the bridge is: k is the number of layers of the bridge; R′ im is the heat dissipation gap radius of the leftmost cable in the i-th layer; r im is the radius of the leftmost cable in the i-th layer, i.e. the maximum cable radius; m is the serial number of the leftmost cable in the i-th layer.

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