JP2006197758A - Power supply device utilizing induced current of overhead ground wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the output power of a power supply device utilizing a split CT in which a core is split without increasing the size of the core or sophisticatedly processing the cut surface of the core. <P>SOLUTION: Two CTs 20a and 20b as a split CT are installed on an overhead ground wire 10, and capacitors C1 and C2 are connected to the output terminals of the CTs 20a and 20b. An induced current passed through the overhead ground wire 10 is taken out by the individual CTs 20a and 20b. Their output currents are rectified through diode rectifiers 40a and 40b, and then supplied to a load through a power conversion circuit 50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a power supply apparatus for supplying electricity to a device used on a power transmission tower, in which a split CT having a core divided is installed on an aerial ground wire installed in parallel with a power transmission line. The present invention relates to a power supply device using an induced current of an overhead ground wire.

  Conventionally, as a power supply device for supplying electricity to the equipment used on the transmission tower, a CT (current transformer) is installed on the overhead ground line installed in parallel with the transmission line, and the overhead ground is generated by the current of the transmission line. There is known a power supply device that takes out an induced current generated in a wire (see, for example, Patent Document 1).

  Among the power supply devices using this CT, those using a penetrating CT that penetrates an overhead ground wire into the CT core split the CT core to facilitate installation and removal from the overhead ground wire. It is preferable to use so-called divided CT (see, for example, Patent Documents 2 and 3).

  However, even if it is a split type CT, the original form is a penetration type CT, so the number of turns of the primary winding is only one turn due to the overhead ground wire penetrating the core. Have difficulty. A large core is required to extract a large amount of electric power. In the case of split CT, the larger the core, the more difficult it is to process the cut surface, and it is difficult to make the core synergistically. There is a point.

In addition, since a gap is generated in the cut surface of the core, the output power is reduced and variations in characteristics are caused, so that there is a problem that the cut surface needs to be highly processed.
Japanese Patent Publication No.55-27530 JP-A-10-257654 Japanese Patent Laid-Open No. 10-142285

  The problem to be solved by the present invention is to increase output power without increasing the size of the core or highly processing the cut surface of the core in a power supply device using a split-type CT in which the core is divided. There is.

  The present invention relates to a power source using an induced current of an aerial ground wire that takes out an induced current generated in the overhead ground wire through an overhead ground wire installed in parallel with a power transmission line in a split type CT core obtained by dividing the core. In the apparatus, a capacitor is connected to the output terminal of the CT.

  According to the present invention, by setting the capacitance of the capacitor connected to the CT output terminal to an appropriate value, the output power can be increased without increasing the size of the core.

  Even if the processing accuracy of the cut surface of the core varies, a large output power can be obtained by setting the capacitance of the capacitor connected to the output terminal of the CT to an appropriate value.

  Furthermore, when output current is taken out from multiple CTs in parallel, a capacitor is connected to the output terminal of each CT to absorb variations in the characteristics of each CT, and an output voltage that allows each CT to take out the maximum output current is practical. It can be matched to the extent that there is no problem.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a basic configuration diagram showing a power supply device of the present invention, and FIG. 2 is an equivalent circuit diagram thereof.

  In FIG. 1, an aerial ground wire 10 installed in parallel with a power transmission line (not shown) is passed through a core 21 of a split type CT 20 obtained by dividing the core 21 into two in the vertical direction. The generated induced current (load current i shown in FIG. 2) is taken out.

As shown in FIG. 2, it is clear that the power consumed by the load resistor _RL increases as the load current i increases. When the capacitor C is not connected to the output terminal of the CT 20 in FIG. 2 (conventional example), the value of the load current i is expressed by Equation 1.

On the other hand, when a capacitor C is connected to the output terminal of CT20 as shown in FIG.

In Equations 1 and 2, ω is the angular frequency of the current flowing through the overhead ground wire, L _P and L _S are inductances, n is the number of windings, I is the current flowing through the overhead ground wire, and Q is the electrostatic capacitance of the capacitor. Capacity.

As can be seen from Equation 2, when a capacitor C is connected to the output terminal of CT20, the first term R _L ² (1-ω ² Q (L _S + _Lp )) ² can be adjusted. That is, if a capacitor C having an electrostatic capacity of Q = 1 / {ω ² (L _S + L _p )} is selected so that the first term of Formula 2 is 0, it is expressed by Formula 1 as a conventional example. It is possible to obtain a value larger than the value of the load current i.

On the other hand, whether the machining accuracy of the cut surface 22 in the core 21 of FIG. 1 affects the magnitudes of the inductances L _p and L _{S in} FIG. 2, particularly the magnitude of L _p . If the processing accuracy is good and the gap between the cut surfaces 22 is small, L _p and L _S are large. Conversely, if the gap is large, L _p and L _S are small. In the present invention, even if the machining accuracy of the cut surface 22 varies, a large current can be obtained by connecting an optimum capacitor C according to the values of the corresponding inductances L _p and L _S. That is, depending on the values of the corresponding inductances L _p and L _S , a large current can be obtained by connecting the capacitor C whose capacitance is Q = 1 / {ω ² (L _S + L _p )} as described above. Obtainable.

  FIG. 3 is an explanatory view showing an embodiment of the present invention. In the embodiment shown in the figure, the first CT 20 a and the second CT 20 b are installed on the aerial ground wires 10 on both sides of the power transmission tower 30. Capacitors C1 and C2 are connected to the output terminals of the respective CTs 20a and 20b, and currents rectified by the diode rectifiers 40a and 40b are connected in parallel. The current thus obtained is supplied to the load via the power conversion circuit 50.

  In the first CT 20a and the second CT 20b on both sides of the power transmission tower 30, the capacitors C1 and C2 connected to the output terminals are connected to the first CT 20a and the second CT 20b as described above. It functions effectively as an adjustment means for increasing the power that can be acquired individually.

  Further, as shown in FIG. 3, when outputs from a plurality of CTs are arranged in parallel, each CT operates with the same output voltage because of the circuit configuration. In this case, unless each CT has the same output voltage from which the maximum output power can be extracted, the power cannot be extracted efficiently. In such a situation, the capacitor connected to the output terminal of each CT absorbs the variation in each CT characteristic, and is effective as a means for adjusting the output voltage at which the CT can take out the maximum output power to a level where there is no practical problem. To work.

  For example, in FIG. 3, by selecting capacitors C1 and C2 having appropriate capacitance values, adjustment is possible to match the output voltages from which the maximum output power of the first CT 20a and the second CT 20b can be extracted. Thus, the capacitors C1 and C2 function effectively as adjustment means for increasing the power that can be obtained from the plurality of CTs as a whole.

  In FIG. 3, the currents from the first CT 20a and the second CT 20b are connected in parallel after passing through the diode rectifiers 40a and 40b, so that the capacitor Cl and the capacitor C2 are not AC-parallel. The adjustment of one CT and the capacitor does not affect the other, and the capacitance (capacitance) can be adjusted independently.

  The present invention can be used as an information transmission device used on a power transmission tower, more specifically, as a power supply device for supplying electricity to a device such as a transmission line maintenance information transmission device.

It is a basic lineblock diagram showing the power supply device of the present invention. FIG. 2 is an equivalent circuit diagram of the power supply device shown in FIG. 1. It is explanatory drawing which shows the Example of this invention.

Explanation of symbols

10 Overhead ground wire 20, 20a, 20b CT (current transformer)
21 Core 22 Core cut surface 30 Transmission tower 40a, 40b Diode rectifier 50 Power conversion circuit C, C1, C2 Capacitor

Claims (1)

  In an aerial ground wire induced power supply apparatus for extracting an induced current generated in an overhead ground wire through an overhead ground wire installed in parallel with a transmission line in a split type CT core obtained by dividing the core, A power supply device using an induced current of an overhead ground wire, characterized in that a capacitor is connected to the output terminal.

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