JPH0720610Y2 - Voltage transformer secondary / tertiary voltage introducing device - Google Patents

Description

[Detailed Description of the Device] A. Industrial Application Field The present invention does not affect the reliability of the secondary / tertiary circuit of the transformer for the instrument, and the secondary / tertiary of the newly required measurement / control device. The present invention relates to a transformer secondary / tertiary voltage introducing device for introducing a voltage.

B. Outline of the Invention The secondary / tertiary voltage introducing device for a transformer of the present invention is a secondary / tertiary winding of a transformer for measuring in which a measuring / control device is connected to the secondary / tertiary side. A voltage divider composed of a high resistance that can obtain a divided voltage suitable for being introduced into the semiconductor circuit is connected in parallel with the ground side, and the divided voltage is newly required for the measurement / control device. By introducing the new introduction circuit, even if a trouble occurs in the new introduction circuit, the main body of the instrument transformer and the secondary and tertiary circuits connected to the main body are not affected.

C. Conventional technology Voltage transformers for meters (hereinafter simply referred to as PT) secondary and tertiary voltages are introduced into meters and relays, and play an extremely important role as the center of the nervous system for operation of the substation. In other words, if a trouble such as a wire break, short circuit, or ground fault occurs in the PT secondary or tertiary voltage circuit, the secondary or tertiary voltage will be lost, or the input value will change and the breaker will open due to malfunction of the relay. And,
Abnormal control is performed by the response of the measurement and control device, and it is extremely likely to trigger a major accident such as a major power outage.

For this reason, the PT secondary and tertiary circuits are not only implemented to maintain high reliability, but are also working to maintain high reliability by limiting the range of use as much as possible.

On the other hand, from the perspective of rationalizing the operation and maintenance of the substation,
The number of cases requiring PT secondary and tertiary voltages is increasing. For example, there is a case in which the voltage value does not have to be accurate, but it is desired to know whether the voltage is present or not, or to know the phase relationship between a certain current and the voltage. Therefore, low cost such as simple PT
A PT may be installed.

FIG. 3 shows an example of the detection of the deterioration of the arrester using the conventional simple PT, in which the arrester 4 and the current detection resistor 5 are connected in series between the transmission line L and the ground, and the terminal voltage of the resistor 5 is banded. It is added to the synchronous rectifier 7 via the pass filter 6. On the other hand, the simple PT8 is connected to the power transmission line L, the secondary side voltage thereof is amplified by the buffer amplifier 9, the waveform is shaped by the signal processing circuit 10, and the synchronous rectifier 7 is synchronized. The current of the arrester 4 advances by 90 ° due to the capacity, but when it deteriorates, a resistance component is generated and an in-phase component current flows. Therefore, the deterioration can be detected by the voltmeter 11 connected to the synchronous rectifier 7. In this example, the secondary voltage of PT8 is used to see the phase relationship with the current,
The voltage value is irrelevant.

D. Problems to be solved by the device Although the simple PT is low cost, not only is it considerably expensive when the PT primary voltage is high, but also the reliability of the entire main circuit is reduced by installing such equipment. Is not preferable.

The present invention has been made in view of such problems of the prior art, and the purpose thereof is
It provides a transformer secondary / tertiary voltage introducing device that uses PT and can introduce secondary / tertiary voltage without affecting the reliability of the conventional PT secondary / tertiary circuit at all. is there.

E. Means for Solving the Problem In order to achieve the above object, the measuring transformer secondary / tertiary voltage introducing device of the present invention has a measuring / control device connected to the secondary / tertiary side. With a high resistance that is connected in parallel to the instrument transformer and the secondary or tertiary winding of this instrument transformer, and can obtain a divided voltage suitable for introducing into the semiconductor circuit between the transformer and the ground side. It is characterized by comprising a voltage divider configured so that the divided voltage can be introduced into a newly required measurement / control device.

F. Action Since the voltage divider is made of high resistance, has a large voltage division ratio, and the divided voltage is taken from the ground side, troubles such as disconnection, ground fault, short circuit, etc. occur in the circuit drawn from the voltage divider. However, it does not affect the PT body and the conventional PT secondary and tertiary circuits.

Also, since the voltage divider has high resistance, the load on the PT does not increase,
Therefore, the divided voltage can be extracted while keeping the accuracy of the PT voltage value high.

G. Examples Examples will be described with reference to the drawings.

Figure 1, in the second view, potential transformer (PT) U 1 of the secondary side S, V, W-phase winding a, b, phase voltages of _{c e u, e v, e} w and 3 Zero phase voltage e _{o in which} each phase winding b ′, a ′, c ′ on the secondary side T is connected in series
Is added to the measurement / control device or relay 3.
The voltage dividers R _u , R _v , R _w , and R _o of the voltage dividing device 2 are configured with high resistance, and the voltage division ratio is 1000R: 10R. Voltage divider R _u , R _v , R _w
Are connected in parallel with the secondary side S windings a, b and c, respectively, and the voltage divider R _o is connected between the tertiary side T windings b ′ and c ′. Phase voltage e _u , e _v , e _w , e _o 1/100 of voltage e _u1 , e _v1 ,
e _w1 and e _o1 are output.

Then, when the divided voltage from the voltage divider is used for the deterioration inspection of the arrester of FIG. 3, for example, if the arrester 4 is connected to the U phase of the transmission line L, the voltage divider R of the U phase is used. _The divided voltage e _u1 of _u is used as an input signal of the buffer amplifier 9 instead of PT8 and is used as a synchronizing signal.

In the above embodiment, the voltage division ratio of the voltage divider is set to 1000R: 10R, but it is not limited to this, and 1000R: 50R, for example, digitized or transistorized to obtain a voltage suitable for the measurement control device. It is sufficient to divide the pressure so that

H. Effect of the Invention Since the present invention is configured as described above, it has the following effects.

Even if a trouble such as a short circuit, a ground fault, or a wire break occurs in the secondary or tertiary circuit drawn from the voltage dividing point of the voltage divider, the voltage transformer is connected to the main body of the voltage transformer and the transformer. It has no effect on the original measurement / control device or relay circuit.

The addition of the voltage divider and the secondary and tertiary circuits drawn from it does not increase the burden on the main body.

The voltage value detected by the secondary / tertiary circuit from the voltage divider can also maintain high accuracy.

Therefore, not only when secondary and tertiary circuits from the voltage divider are required as auxiliary, but also when high accuracy is required, the simple PT
It is possible to meet the request without any trouble to the PT main body without newly installing etc.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram of a voltage divider, and FIG. 3 is a conventional arrester deterioration detection circuit diagram. 1 ...... instrument transformer, 2 ...... partial pressure device, R _u to R _d ...... divider.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01F 38/24

Claims (1)

[Scope of utility model registration request] 1. A transformer for an instrument, to which a measuring / controlling device is connected on the secondary / tertiary side, and a secondary / tertiary winding of the instrument transformer, which are connected in parallel to each other and to the earth side. And a voltage divider composed of a high resistance capable of obtaining a divided voltage suitable for being introduced into a semiconductor circuit, and so that the divided voltage can be introduced into a newly required measurement / control device. A secondary and tertiary voltage introducing device for an instrument, characterized in that