JPS6084917A - Display wire protecting relaying device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an indicator line protection relay device that takes into account improvement in the performance of an indicator line relay.

[Technical background of the invention and its problems]

Figure 1 is a conventional system system diagram of a protective relay device in a two-terminal power transmission system.

A protected power transmission line 11 is provided between the B ends.

Circuit breakers 12A and 12B are connected to the A and B ends of both electric stations, and the current at each end can be introduced into input conversion sections 20A and 20B via current transformers 13A and 13B.

After being converted in the input conversion units 20A and 20B, it is sent to the suppression elements 14A and 14B, and then sent to the display line length compensation circuits 17A and 17B, as well as the operation element 15.
A.

15B, and is sent to isolation transformers 16A and 16B. The signal is also transmitted to the end of the serial number through the display line 18 via the isolation transformers 16A and 16B of each terminal.

Here, operating elements 15A, 15B, suppressing elements 14A, 14
The presence or absence of an accident on the υ power transmission line 1.1 is determined based on the magnitude of the current flowing through B.

And the final decision is the circuit breaker 12A at each electrical station.

It is output as a tripping command to 1213. In addition, the electrical quantities iA and IB of each electric station are used for the constant value, but in general, the display line maintenance and relay power formula can be expressed as Equation (1) if the errors of transformers are ignored.
When an external fault occurs, the current at each end is zero, and when an internal fault occurs, the differential current becomes large.

K<IiB1... (1) (K is a constant) However, in a simple differential like equation (1), the display line may change due to the error of the current transformer at each end and the saturation 3Jl phenomenon in the event of an external fault. Since there is a possibility that a relay may operate unnecessarily, it is common to provide a ratio characteristic, which is expressed as in equation (1).

ΣIt- to Σ1tk1〉■ (o, (2) (Ik is the current at each terminal; and Ko is the relay constant) However, in the conventional display wire relay, 44, which outputs only the amount of electricity at the other end, is unfortunate due to the circuit configuration, In the case of Figure 1, the operating formula of this indicator line relay is formula (3)
It will be like this.

The same ik indicates the current at each end, and at the A end, the electrical quantity iA, B
At each end, the electric quantity iB is shown.

(iA+iE) -Kik≧I(o -...(3)(
``A + ''B tri operation amount; Kik is suppressed 5k;
Kr I (o is a constant) Fig. 2 shows an example of the ratio characteristics of an indicator line relay, and shows the characteristics at the A and B ends when an internal fault F occurs.

Considering the internal accident F in Fig. 1 using equation (3), the operating amount of the indicator line relay is the electrical amount (iA+iB), which is the same at both ends.

In Figure 2, 31 is the external accident trajectory, 32 is the B-end physical property, and 3
3 indicates the A-end physical properties, and 34 indicates the operating range.

However, the amount of suppression at the A end is suppression + 17 IJ amount KiA,
At the B end, the suppression amount is KiB. Here, the quantity of electricity iB is approximately zero since it is a non-power supply terminal, and the amount of υ suppression is hardly applied, so the indicator line relay tends to operate.

In other words, the reason why the ratio characteristics at both ends in FIG. 3 are different is that the amount of suppression at each end is determined by the current flowing through the suppressor element in FIG. 1.

If the ratio characteristics of each terminal are different in this way, in the case of internal fault F in Figure 1, terminal B of the no-current terminal has a small amount of suppression and tends to operate, but terminal A has a large amount of suppression and does not operate. It becomes a trend.

For this reason, conventional display line maintenance theory: In electrical equipment, the ratio characteristics of the display line relay at each terminal differ depending on the current at each terminal, and there is a possibility that the accident cannot be eliminated depending on the current at each terminal at the time of an internal accident. .

[Purpose of the invention]

The present invention was developed with the aim of solving the above problems, and even if the current at each terminal at each electric station is different,
′? For display wires of J terminal; Display wire maintenance side tie that ensures that the characteristics of the electrical appliances are the same and that the transmission line within the insured section is securely maintained without being affected by the current at each terminal; Electrical equipment certification I will provide a.

[Summary of the invention]

The present invention includes current transformers installed at one end and the other end of a power transmission line,
A conversion section that transforms the secondary current of this current transformer, an isolation transformer that insulates a part of the output electricity of this conversion section, and one side of the winding that is insulated to a different potential by this isolation transformer. The display wire that is connected and the other end is connected to the isolation transformer on the other end side, and the amount of electricity inputted to the isolation transformer on the own end side among the output electricity amount of the converter is determined by the number of lengths of the display wire. In the display wire maintenance relay device, which consists of a compensation circuit for correction, a self-end current derivation circuit that derives the electrical quantity of the conversion section on the end side, and a current derivation circuit that is connected in parallel to the isolation transformer via the compensation circuit. A display line current derivation circuit that derives the amount of electricity flowing in the display line, and a judgment circuit that is connected to the display line current derivation circuit and the self-end current derivation circuit and determines whether there is an accident on the power transmission line. This is a display line maintenance relay device.

That is, in the present invention, in a display line three-voltage device whose image is to be maintained at n terminals (n>z), each terminal is configured to be connected to each other by a pair of display lines, thereby reducing the self-terminal current. The operation formula (Id-L
Kk(Ik-Id)'')+(jd-convexKk'(Ik-I
d) )k-1 = 1 > 1 (.This is a display line maintenance relay device whose function is to determine internal and external accidents.

Indicates that it only works during negative periods.

[Embodiments of the invention]

Next, the present invention will be explained in detail. FIG. 3 shows current transformers 13A, 13B installed at one end A and the other end B of the power transmission line 11, conversion units 20A and 20B that transform the secondary current of the current transformers 13A and 13B, and conversion isolation transformers 16A and 16B that insulate a portion of the output electricity of the sections 20A and 20B;
An insulating transformer 1 with one end connected to windings insulated to different potentials by disconnection transformers 16A and 16B, and the other end connected to windings insulated to different potentials.
Display line 18 connected to 6B and 16A, and converter 20A
, 20B, the insulation transformer 16A on the self-end side of the output electricity quantity.
, 16B, a display line protection layer consisting of compensation circuits 17A and 17B that correct the amount of electricity flowing into the display line 16B according to the number of spanning lengths of the display line 18;

A self-end current deriving circuit 21A that derives the amount of electricity of 20B.

21B, and display line current deriving circuits 22A and 22B that are connected in parallel to the isolation transformers 16A and 16B via the compensation circuits 17A and 1.7B and derive the amount of electricity flowing to the display line 18.
A display line maintenance goose relay comprising display line current deriving circuits 22A, 221J and self-end current deriving circuits 21A, 21LIK are connected to judgment circuits 23A, 23B for determining the presence or absence of an accident on the power transmission line 11. The device is shown.

In Fig. 3, 21A is a circuit that derives the output of the current transformer 13A using an auxiliary current transformer, etc., and 22A derives the electrical quantity including the own end current and the opposite end current. 23A indicates a determination circuit which introduces the outputs of the circuit 21A and the circuit 22A and determines whether an internal or external accident occurs.

Here, the circuit 22A will be explained.

Introducing the secondary currents of current transformers 13A and 13B at both ends of A and B in FIG. 1 to input converting sections 20A and 20B, respectively,
They are interconnected by display lines 18.

Next, pay attention to end A in FIG. First, if we consider one person's electrical quantity on the secondary side of the current transformer 13A in the direction shown in the figure, the electrical quantity will flow through the display line current deriving circuit 22A via the supplementary circuit 17A.
and is shunted to the circuit of the display line 18 via the isolation transformer 16A. Here, the shunt ratio is determined by adjusting the internal circuit of the compensation circuit 17A, and the current is shunted to the iAl side at a ratio of p and to the iA2 side at a ratio of q. On the other hand, since the electric current Ill is also divided in the same way as the electric board, considering this as a whole, iAl = l
A+QIE I IA2=qIA-qIB. Here, if p=q=, the result is that the quantity of electricity k·(iA+iE) is introduced into the display line current deriving circuit 22A.

The display line current deriving circuit 22A is electrically fAk (IA + IB
) to the judgment circuit 23A using an auxiliary current transformer etc.
This is for introducing 10 iB, and the current transformation ratio of the auxiliary current transformer is /
], then the determination circuit 23AK electric quantity iA+IB is introduced. 21A is a self-end current derivation circuit.

In FIG. 4, a description will be given of the intermediate j' constant circuit 23A lfi in front of the maintenance and excitation introduction Σ electrical equipment installed at the A end, but the explanation will be omitted since the B end is also the same.

In FIG. 4, 41 is an adder, and the electric quantity iA at its own end
The output of the circuit 22A, iB, is analysed, and the electricity at the other end is derived.

42 is a combiner which combines the electricity iiB output from the adder 41 and the quantity of electricity iA, and derives the difference quantity of electricity id.

Reference numeral 43 is an adder which adds the outputs of the electric plate and the combiner 42 to produce the electric quantity IA-Id.

An adder 44 adds the output of the adder 41 and the output of the combiner 42 to produce an electrical quantity IB-L.

Reference numeral 45 denotes a suppression amount generating circuit which serves as the output of the adder 43 and the output of the adder 44, and its output is introduced into the determination section 46.

The determination unit 46 uses the output of the synthesizer 42 and the suppression amount creation circuit 45.
An internal/external accident of the protected power transmission line 11 is determined based on the derived electrical quantity, and if an internal accident is determined, a trip command 24A is issued to the breaker 12A.

Next, the operating formula of the display fiber electric appliance will be explained.

Thus, the electrical quantity Id=IA+'n is obtained as the output of the combiner 42.

The suppression amount Ike· brings the outputs -Id and IB-Id of the adders 43 and 44 to the suppression amount creation circuit 45.

In addition, in the determination section 46, the outputs of the combiner 42 and the suppression amount creation circuit 45 are used to determine internal and external accidents using the operation determination formula of equation (4).
Set.

The suppression amount 1k in equation (4) is the sum of the air volumes at each end (Kmu(
The plus sign indicates that the movement amount i is only suppressed between the intercostals when it is positive.
? If the amount of Il is required, it is processed in the processing unit 46. Further, the minus sign is processed by the determination unit 46 so that the suppression amount is applied only to the intercostal space whose motion amount id is negative.

(English a-ΣKh (English h-Ia) + (”, −Σ, (
Ik-i, )-) 〉Ko-(4)k=^ l(-A (Akira Kb(ih Ia)1 suppression amount i, ,; K, ,
0 is a constant) k''A In this way, by obtaining the operating formula of the display wire relay as shown in equation (4), it is possible to achieve the same relay characteristics for both terminals A and B, and characteristics that are not affected by the current at each terminal. It is possible to eliminate accidents at each end.

When the response waveform at the time of an internal accident is shown in FIG. 5 as the output of each element in FIG. Figure 5 (
b) is the electrical quantity i□10iB, FIG. 5(C) is the electrical quantity iB of the output of the adder 41, FIG. ) is the electrical quantity 1 person-1d of the output of the adder 43, FIG. 5(f) is the electrical quantity 1B-id of the output of the 711J calculator 44, and FIG. This shows the output of the k-mu unit 46. Also, the response waveform in the event of an external accident is shown in FIG. 6, where the suppression amount jkea becomes large with respect to the operation amount i, resulting in no operation.

Kk in Shobu (4) is a suppression coefficient, and the coefficient can be set arbitrarily according to the current transformer at each end, and is selected so as not to malfunction in the event of an external accident.

6 (aJ is the electrical quantity iA, Fig. 6(b) is the electrical quantity iA+iB, Fig. 6(C) is the electrical quantity iB of the output of the adder 41, and Fig. 6(d) is the instruction generator. 42 output electricity quantity i6,
FIG. 6(e) shows the amount of electricity i□10i6 at the output of the adder 43,
FIG. 6(f) shows the electrical quantity i,, -i, of the output of the adder 44.
, FIG. 6(g) shows 46 outputs.

Although the present invention has been described using a two-terminal display line maintenance relay device as an example, the same effect as described above can be obtained even in a three-pin power transmission system by constructing the relay device as shown in FIG.

In addition, when introducing a counterpart electrical quantity, it is sufficient to provide the number of display line pairs for the counterpart terminals, but since the system becomes a multi-terminal system (7), the number of display line pairs increases, which is economically inferior. Therefore, the present invention has fewer display lines and is dynamic.

〔Effect of the invention〕

As explained above, according to the present invention, the display wire relay characteristics at each end can be made the same, and each terminal can be equally thickened.
In addition, unbalanced operating times can be reduced and maintenance and inspection work can be simplified.

Further, it is possible to provide a display line protection relay system that uses a small number of display line pairs.

[Brief explanation of the drawing]

Figure 1 is a system diagram of a conventional display line protection relay system, Figure 2 I
-1, Figure 1 is a ratio characteristic diagram of the display line relay, Figure 3 is a system diagram of the display line protection 11 electric device showing one embodiment of the present invention, and Figure 4 is a configuration diagram of the determination circuit shown in Figure 3. , M5 is an explanatory diagram of the action of the display wire relay according to the present invention in the event of an internal failure, Figure 6 is an explanatory diagram of the response in the event of an external n failure of Figure 5, and Figure 7 is an illustration of the response in the case of a three-terminal system. It is a system configuration diagram. 14A: Suppression collector 15A: Operating system element 16A: Isolation transformer 17A: Compensation circuit 18-: Display line 20A
- Father exchange unit 21A... Self-end current derivation circuit 22A... Display line current derivation circuit 23A... Judgment circuit 41, adder 42, synthesizer 45, suppression amount creation circuit 46, judgment section

Claims (1)

[Claims] A current transformer installed at one end and the other end of a power transmission line, a conversion section that transforms the secondary current of the current transformer, and an isolation transformer that insulates a part of the output electricity of this conversion section. , an indicator wire whose one end is connected to a winding insulated to a different potential by this insulating transformer and whose other end is connected to the insulating transformer at the other end; In an indicator wire relay/type device comprising a compensation circuit that compensates for the amount of electricity flowing into the insulating transformer by the number of lengths of the indicator wires, there is a control circuit for deriving the amount of electricity of the converter on the self-end side. an indicator line current deriving circuit that is connected in parallel to the insulating transformer via the compensation circuit to derive the amount of electricity flowing in the indicator line; An indicator line protection relay device comprising: a power supply circuit connected to an end current derivation circuit to determine whether or not there is an accident on the power transmission line;