JPH0728497B2 - In-phase 2-way flat laying power cable phase arranging method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a phase arrangement sequence for laying a three-phase power cable with two in-phase two lines in a flat shape and between two adjacent spans. The present invention relates to a method of arranging phases of a two-phase flat laying electric power cable of the same phase.

[Summary of the Invention] The present invention is a two-phase in-phase two-phase in-phase power cable, in-phase two-line flat laying electric power for laying flat in a line unit in the laying width direction and between adjacent spans. In the cable phase arranging method, the two-phase three-phase power cable has three spans as a unit, and in the first span in each unit, the two lines are viewed as a whole and the same phase of one phase is present at both ends in the laying width direction. The power cables are respectively located, and the remaining two-phase power cables are 2 in the laying width direction.
Arrange the lines so that they are located in the same phase order,
By arranging the first span and the second span and the second span and the third span in the same direction as seen in the laying width direction, the sheath induced voltage is suppressed and the span length is increased. The number of connections is reduced.

[Prior Art] When two-phase power cables are used for one phase and three-phase power cables are laid in a two-line flat shape and between adjacent spans, the same phase may be used depending on the arrangement order. An impedance imbalance occurs between power cables,
An imbalance occurs in the current flowing through the common mode power cable. In order to balance the currents flowing through the power cables between the same phases, the conventional method is to use the second standard as stipulated in the Japan Cable Industrial Standard "Allowable Current for Power Cables", Part 1 JIS No. 168D (1980).
The phase arrangement was as shown in the figure. In the figure, 1 is the ground, 2 is a cable laying groove provided under the ground 1, and 3 is U
Phase, V phase, W phase and U'phase, V'phase, W'phase, 3 each
It is a two-phase power cable for the phase. That is, the phase arrangement of FIG. 2 is a target phase arrangement centered on the center between both lines.

[Problems to be Solved by the Invention] When the three-phase power cable 3 is laid flat with two in-phase wires in this way, an induced voltage is induced in the metal sheath by the conductor current flowing in the cable conductor of each phase. It The induced voltage in the case of the phase arrangement in Fig. 2 is about 1.2 times as large as in the case of one line (three cables).

The reason for this is that as shown in Fig. 3, the spacing between the power cables 1 is 300 KV, with a cable spacing of 320 mm in the same line and an inner cable spacing of 760 mm between adjacent lines, conductor size of 1600 mm ² , single core The case of the OF cable will be described as an example. As shown in Fig. 3, in the case of flat laying of two in-phase wires, as described in P23 of JCS No. 168D (1980), a phase arrangement that does not cause impedance imbalance in the in-phase power cable 3 Is a target arrangement array centered on the center between both lines, the sheath induced voltage V _max is the conductor current I (ampere), and the length of one span of the power cable is L.
(Km), V _max = 0.180I × L (V). Since the sheath induced voltage in the case of 3 lines per line (3 lines on the left side or 3 lines on the right side) is V _max = 0.147I × L (V), 0.180 / The induced voltage is 0.147 = 1.2 (times). However, in this case, the impedance is 0.0148 + j0.190 (Ω / Km) in any power cable 3 (6 power cables), and there is no impedance imbalance.

Such a sheath trigger voltage is set to a specified value (typically 65
V, 100 V in Saudi Arabia) It is necessary to shorten the span length of the power cable 3 in order to make it less than 100 V. Therefore, the number of connecting parts is increased, which causes a cost increase.

An object of the present invention is to provide a phase arranging method for a two-phase flat laying power cable of the same phase, which can suppress the sheath induced voltage to increase the cable span length and reduce the number of connecting portions.

[Means for Solving Problems] A configuration of the present invention for achieving the above object will be described with reference to FIG. 1 corresponding to an embodiment. The present invention provides a three-phase power cable 3. A phase arranging method of a two-phase in-phase two-line flat power cable in which two lines are laid flat in a line unit in the laying width direction and between adjacent spans. 3 is a unit of 3 spans, and in the 1st span in each unit, one line of the common-mode power cable 3 is located at both ends in the laying width direction when viewing the two lines as a whole, and the power of the remaining two phases is used. The cables 3 are arranged in the laying width direction so that both lines are located in the same phase order, and are viewed in the laying width direction between the first span and the second span and between the second span and the third span. Phased in the same direction.

[Operation] In the phase arrangement of the present invention, the sheath induced voltage V _max is V _max = 0.156I × L (V) when the intervals between the power cables 3 are the intervals shown in FIG. 3 described above. In the case of the phase arrangement of the present invention, it is 0.156 / 0.180 = 0.87 (times), that is, 87% compared with the case of the phase arrangement of FIG.

Also, with 3 spans as one unit, at each position of the insulating connection portion 4 between the first span and the second span and within the unit, at the position of the insulating connection portion 4 between the second span and the third span, When all the power cables 3 are suspended in the same direction, the impedance of each phase becomes as follows while maintaining the phase arrangement of the above conditions in each span, and the impedance imbalance in the same phase
It is 0.5% or less, which is practically no problem. _u = _v = _w = 0.0112 + j0.187 (Ω / Km) _{u ′} = _{v ′} = _{w ′} = 0.0184 + j0.187 (Ω / Km) Also in FIG. Examining the relationship of the sheath induced voltage when the length is set to 320 mm, the sheath induced voltage V _{max in} the case of the conventional phase arrangement shown in FIG. 2 is V _max = 0.2075I × L (V), whereas the first The sheath induced voltage V _{max in} the case of the phase arrangement of the present invention shown in the figure is V _max = 0.165I × L (V), which is 0.165 / 0.2075 in the case of the phase arrangement of the present invention as compared with the phase arrangement of FIG. = 0.80 (times), that is, it decreases to 80%.

Embodiment An embodiment of the present invention will be described in detail below with reference to FIG. The present invention provides a phase array in which each three spans are repeated. FIG. 1 shows an example of the phase arrangement of one unit. As for the power cable 3, two lines, a first line 5A and a second line 5B, are laid in a flat shape as shown in the drawing in a line width direction. In the first span of one unit shown in the figure, one phase, that is, U-phase or U′-phase common-mode power cable 3 is arranged at both ends in the laying width direction of the second line as a whole, and the remaining two lines are arranged. The V-phase, W-phase and V'-phase, W'-phase power cables 3 which are phases are V-phase in the same phase order in both lines in the laying width direction.
Phase, W phase, and V'phase, W'phase are arranged.

At the location of the insulating connection portion 4 of each phase between the first span and the second span, and the location of the insulating connection portion 4 of each phase between the second span and the third span, the power cable 3 of each phase is provided. See all in the laying width direction and lay each in the same direction. Therefore,
The phase arrangement of each power cable 3 in the second span is W phase, U
Phase, V phase, U ′ phase, V ′ phase, W ′ phase, and the phase arrangement of each power cable 3 in the third span is V phase, W phase, U phase, W ′ phase, U ′.
Phase, V ′ phase. Also in these second and third spans, one phase of the in-phase power cable 3 is located at both ends in the laying width direction when viewing the two lines as a whole, and the remaining two-phase power cables 3 are 2 in the laying width direction. The lines are also arranged in the same phase order. However, in each span, the arrangement of the phases is sequentially switched, and in the three spans, the phases are generally switched.

The phase arrangement order of the first span is not limited to the order shown in FIG. 1 and may be the phase arrangement order shown in the second span or the third span.

[Effects of the Invention] As described above, according to the method of arranging the phase of the two-phase flat laying power cable of the present invention according to the present invention, the impedance induced imbalance in the same phase is suppressed to 1% or less and the sheath induced voltage is compared to the conventional one. Can be reduced to about 85%. Therefore, even if the sheath induced voltage is regulated to a certain voltage, the cable span length can be made 1.15 times longer than before, the number of connecting parts can be reduced by about 15%, and the installation cost can be reduced. it can.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a phase arrangement order according to the present invention,
FIG. 2 is an explanatory diagram of a conventional phase arrangement order, and FIG. 3 is an explanatory diagram showing an example of intervals between power cables of respective phases. 3 ... Power cable, 4 ... Insulated connection, 5A ... 1st line, 5B ... 2nd line.

Claims (1)

[Claims] [Claim 1] Two lines of three-phase power cable with in-phase two articles,
In the phase arranging method of the in-phase two-section flat laying power cable, which is laid flat in a line unit in the laying width direction and laid between adjacent spans, the three-phase power cable of the two lines has a unit of three spans. In the first span within each unit, one line of common-mode power cable is located at both ends in the laying width direction when viewing the two lines as a whole, and the remaining two-phase power cables are 2 in the laying width direction.
Arrange the lines so that they are located in the same phase order,
A phase arranging method of a two-phase flat laying power cable of the same phase, characterized in that the first span and the second span and the second span and the third span are arranged in the same direction in the laying width direction.