JPS59138960A - Voltage divider - Google Patents

Abstract

PURPOSE:To improve the response characteristics of DC transmit voltage measurement by installing a resistance which constitutes a voltage dividing circuit in an enclosed type pressure container and arranging an electrode which forms capacitance parallel to the resistance at specific distance from a lead-out terminal on a high voltage side. CONSTITUTION:A line terminal 3 and a conductor 4 for connection are fixed to the upper part of the enclosed type pressure container 1 with an insulating spacer 2 between, and the upper terminal of a resistor R1 is connected thereto through a high-voltage shield 5. The lower terminal of the resistance R1 is connected to the lead-out terminal 8 fixed to the lower part of the container 1 by an insulating plate 6 and a cover plate 7. The insulating spacer 2 is provided with a shield ring 11 concentric with a line terminal 3, forming capacitance C1 between the ring 11 and terminal 3. The ring 11 and lead-out terminal 8 are connected to one terminal of the parallel circuit of a resistance R2 and capacitance C2, and the resistors R1 and capacitors C1 and C2 constitute a resistance capacity voltage divider for DC transmit voltage measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a voltage divider used to measure DC voltage in a DC power transmission system.

[Technical background of the invention and its problems]

As shown in Figure 1(a), the voltage divider used to measure high voltage includes a resistor R for measuring DC voltage and impulse voltage.
A resistive voltage divider consisting of a series circuit of 1pR2, Fig. 1(b)
As shown in Fig. 1(c), a capacitor voltage divider consisting of a series circuit of a resistor R1tR2 and a capacitor c+pcz is used for measuring AC voltage and impulse voltage, and as shown in Fig. 1(c), for measuring DC voltage and DC impulse voltage. 2. Description of the Related Art A resistor-capacitive voltage divider and the like are known, which are composed of a parallel circuit of resistors R1 to R4 and a capacitor C8.

The voltage divider described above is configured for indoor use,
It is usually installed indoors with a high-voltage side outlet. On the other hand, recently
In order to put DC power transmission into practical use, it is necessary to measure the DC transmission voltage outdoors in order to control and protect the DC power transmission system. In such a case, considering that a resistive capacitive voltage divider is used outdoors as the above voltage divider, it is possible that the high voltage side (under test The equivalent impedance changes from the system) and the voltage division ratio as a voltage divider changes, making voltage measurement inaccurate and unsuitable for practical use.

Furthermore, compared to conventional voltage dividers, the voltage divider used to measure the DC transmission voltage needs to lower the equivalent impedance seen from the high voltage side and increase the capacitance (VA).

In a resistor-capacitive voltage divider, lowering the equivalent impedance is achieved by lowering the resistance value, increasing the capacitance value, and increasing the detected current value. However, when the detected current value is large, the power loss in the resistor increases, and an effective means to absorb this power loss becomes necessary.

Furthermore, when attempting to control and maintain a DC power transmission system using the current detected by the voltage divider described above, response characteristics become a problem. This will be explained below with reference to FIG.

FIG. 2 is a characteristic diagram showing the relationship between resistance value, response characteristics, and power loss, taking a resistive voltage divider as an example. In Figure 2, A
indicates a response characteristic of 1 and is based on the theoretical formula Tns·RC. where TD=response time, R is the resistance value of the resistive voltage divider, and C is the stray capacitance that the resistance of the resistive voltage divider has with respect to the tank.

In FIG. 2, B indicates the power loss W (watts) when 500 kV is applied to the resistive voltage divider. As shown in Figure 2, increasing the resistance value RM (MΩ) reduces power loss and eases thermal manufacturing conditions, but increases response time and is not suitable for high-speed control of DC transmission systems. become unable.

On the other hand, the response time for normal control and purulent preservation is required to be at most 5 [m5ec] or less, and in order to satisfy this condition, a resistance value R or 800 MΩ is required. A commonly used voltage divider vessel is capable of dissipating heat of 100 W/m2, but the resistance I'ilIRM is 800 MΩ.
In this case, the power loss is 3()OW, and in order to satisfy the above characteristics, the structure of the container etc. must be restricted.

[Purpose of the invention]

The present invention was made based on the above circumstances, and its purpose is to provide a voltage divider that has high-speed response characteristics and can be used outdoors when measuring DC transmission voltage. It is in.

[Summary of the invention]

In the voltage divider according to the present invention, high-voltage side and low-voltage side outlet terminals are led out from a closed pressure vessel through an insulating member, and electricity is supplied to the high-voltage side and low-voltage side outlet terminals in the sealed pressure vessel. and a first capacitive element forming a parallel circuit on the high voltage side together with the first resistive element connected to the high voltage side. The above object is achieved by grounding one end of the low-voltage side parallel circuit consisting of the second resistance element and the second quantity elements, and connecting the other end to the low-voltage side outlet terminal. It is something.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.
The figure is a configuration diagram showing one embodiment of a voltage divider according to the present invention. In FIG. 3, 1 is a closed pressure vessel (hereinafter referred to as a vessel). An insulating spacer 2 is placed on the top of this container 1 to insulate it from the container 1, and a line terminal 3 and a connecting conductor 4 are provided.
, the upper end of the resistor R1 is electrically connected via the high voltage shield 5, and the lower end of the resistor R1 is insulated and sealed from the container 1 by an insulating plate 6 and a lid plate 7 to the lower part of the container 1. The lead terminal 8 is drawn out by straining. In the figure, 9 is an insulating tube for supporting the resistor R1, and 1o is an insulating gas such as S[i'6 gas filled in the container 1. In the above, the line terminal 3 housed in the container 1 is fixed to the container 1 by the insulating spacer 2, and the lower part of the insulating cylinder 9 for supporting the Mannobe antibody is fixed to the lid plate 7 at the lower part of the container 1.

Further, a shield ring 1) for mitigating the electric field is installed concentrically with the insulating base 1 td and the line terminal 3, and a first electrostatic A capacitor c1 is formed. Furthermore, the shield, the ring 11, and the lead terminal 8 are connected to the metal container 12.
One end of a parallel circuit consisting of a second resistor R2 and a second capacitor C2 housed in is electrically grounded, and the other end is grounded. The voltage divider having the above structure is shown in terms of an electric circuit as shown in FIG. That is, in FIG. 4, a high voltage side parallel circuit with a first resistor R1 and a first capacitor C1, and a second resistor R2
, the second capacitor tCZ and the low voltage side parallel circuit are connected in series. In the above, the first and second resistors R1 and R2 and the first and second capacitors CI.

C2 is set to a value that satisfies the relationship C, R1=C2R2. The voltage division ratio as a voltage divider is approximately 17,500.

Next, the operation of this embodiment configured as described above will be explained. As shown in the equivalent circuit of FIG. 4, this embodiment generally corresponds to a resistor-capacitance voltage divider according to the classification of voltage dividers shown in FIG. This becomes an equivalent circuit.

As shown in Figure 5, the resistor R1K &
-1, ground capacitance Cg (Cg=Cg1+Cg2+・-
・+Cgn) exists. This ground capacitance C is the capacitance formed by this embodiment 9. Compensate for υ by C2.

Next, in this example, resistor R15R2 + capacitor CI#C
The setting value of 2 will be described. FIG. 6 is a characteristic diagram showing the relationship between frequency (Hz) and voltage division ratio (correspondence) in this embodiment. As shown in the figure, the time constant of the high voltage side parallel circuit is 01
As J applies more force, (curve a r 1) + C
The time constant CI R1O value increases in the order of +d. ) A drop in the partial pressure ratio occurs especially near I Hz. In this case, it can be seen that if the resistor R1O value is a constant value, the smaller the capacitance ciO value, the greater the degree of fall in the voltage division ratio. Therefore, in practical use, for example, 50
For 0 kV, considering the above characteristics, resistor R1
is 2000MΩ, resistor R2 is 400Ω, capacitance C1 is 20 pF, and capacitance C2 is 100 nF. By setting various constants in this way, the fluctuation of the partial pressure ratio can be reduced by ±1
This makes it possible to suppress the damage to less than the attack level. In addition, since the main partial pressure absorption absorber is housed in the container (closed pressure vessel) 1, the function will not deteriorate due to wind and rain even if used outdoors.

The present invention is not limited to the above embodiments.

For example, the insulating spacer 3 in the embodiment shown in FIG.
If the capacitance C1 formed between the shield 1 and the electric field mitigation shield 1 is insufficient, as shown in FIG. A line terminal 13 with a long dimension is used so as to be installed, and an electrode 14 is installed inside the metal cylinder 12.

With the above configuration, the capacitance C1 can have a large value, and the voltage division ratio can be improved as explained in FIG. 6.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without changing the gist of the present invention.

〔Effect of the invention〕

As described above, according to the present invention, the high voltage side and low voltage side lead terminals are led out from the closed pressure vessel via the insulating member, and the high voltage side and low voltage side A first resistance element electrically connected to the output terminal is housed, and an electrode forming a first capacitance element forming a high voltage side parallel circuit together with the first resistance element is connected to the high voltage side output terminal at a predetermined position. The configuration is such that one end of the low-voltage side parallel circuit consisting of the second resistance element and the second capacitance element is grounded, and the other end is connected to the low-voltage side outlet terminal, so that it can be used outdoors. It is possible to provide a voltage divider that can be used in

[Brief explanation of drawings]

Figure 1 (a), (b) l (e) is a circuit diagram showing the classification of voltage dividers, Figure 2 is a characteristic diagram showing the characteristics of a resistive voltage divider, and Figure 3 is a diagram showing the characteristics of a voltage divider according to the present invention. 4 and 5 are circuit diagrams showing electrical equivalent circuits of the voltage divider shown in FIG. 3; FIG. 6 is a characteristic diagram for explaining the present invention in detail; FIG. 7 is a first diagram showing another embodiment of the present invention. 1... Sealed pressure vessel, 2... Insulating spacer, 3...
...Line terminal, 4...Connecting conductor, 5...High voltage shield, 6...Insulating plate, 7...Lid, 8...Output terminal, 9...Insulation for supporting resistor Cylinder, 10... Insulating gas, 11... Shield ring, 12... Metal cylinder, 13... Line terminal, 14... Electrode, R,... First resistor, R2. ...Second resistor, C1...first
capacity, C2... second capacity. Applicant's representative Patent attorney Takehiko Suzue Figure 1 (a) (b) (c) I (PA) Figure 3

Claims (1)

[Scope of Claims] A closed pressure vessel, a high voltage side and a low voltage side outlet terminal led out from the closed pressure vessel via an insulating member, and a high voltage terminal housed in the closed pressure vessel and connected to the high voltage side. a first resistance element electrically connected to the high voltage side and the low voltage side output terminal; and the high voltage side output terminal forming a first capacitance element forming a high voltage side parallel circuit together with the first resistance element. a low-voltage side parallel circuit consisting of an electrode installed at a predetermined distance from the terminal, a second resistance element, and a second capacitance element, one end of which is grounded, and the other end of which is electrically connected to the low-voltage side output terminal. A voltage divider consisting of.