JPH0345118A - Detecting relay for direct current variation - Google Patents

Abstract

PURPOSE:To detect current variation accurately even when a train is passing, under powering condition, through a section by detecting down stream current and train load current sequentially in time series thereby detecting current variation. CONSTITUTION:A downstream detecting means 2 samples DC current flowing through a downstream feeder with predetermined timing and stores time series data thereof. A train load detecting means 3 samples DC current to be consumed by the train with predetermined timing and stores time series data transmitted on a transmitting means. A current variation detecting means 4 calculates the difference between downstream current IL and train load side current IM and calculates current variation I if the calculated difference is positive. When the current variation I exceeds over a predetermined value, a decision means 5 makes a decision that a short circuit fault occurred on the feeder and provides a relay command for operating a relay.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a direct current change detection relay used for protecting feeder lines of a direct current electric railway.

(Prior Art) Current change detection relays that respond to changes in the current flowing through the feeder line have conventionally been used to protect feeder lines in DC electric railways.

Since the detection principle of this type of relay is already known, a detailed explanation will be omitted, but the outline will be as follows. 7th
Figure (a) is a conceptual diagram explaining the principle of a current change detection method, in which a capacitor C and a resistor R are used to detect a change ΔI in the feeder current I. As shown in the figure, this circuit is a differential circuit of C and R, and the variation current Δ■ is obtained by the function: td: time constant (=CH).

Although FIG. 7(a) shows an example of an analog circuit in order to explain the principle of the current change detection method, the same principle can also be realized by digital calculation by a microcomputer. This will be discussed later.

FIG. 7(b) is a waveform diagram illustrating the response in FIG. 7(a), where (a) is a time chart of the feeder current I, and (b) is a time chart of the changing current ΔI. . figure(
Considering the case where a short-circuit accident occurs at time t, as shown in b), the feeder current ■ increases after this time. In response to this current change, a changed current Δ■ is obtained as shown in the figure (b). When the changed current ΔI exceeds a predetermined set value ko, the relay will produce an operating output. In the case of normal current changes, ΔI will not exceed this set value ko, but if a short circuit occurs in the feeder line, the change in feeder current will be extremely large, and Δ■ will also change accordingly. It became large and exceeded the set value ko! 1. Electric appliances work.

In this manner, by determining the magnitude of ΔI, it is possible to select whether the current flowing through the feeder line is a load current, a fault current, or a fault current.

In addition, a protected feeder line generally consists of two sections: an upstream open section and a downstream section. This will be explained using FIG. 8th
Figure (a) is a configuration diagram illustrating a DC feeding system, in which 81 is a rectifier for converting AC electricity into DC electricity, 82 is an upstream feeding line, 83 is a downstream feeding line, 84 and 85 It is a breaker. Further, the upstream open electric wire 82 and the downstream feeder wire 83 are connected at a section 86. Upstream and downstream 1
The river power lines 82 and 83 are each protected by a direct current change detection relay 8. In FIG. 8(a), the rectifier 8
The amount of DC electricity converted in step 1 is supplied to the upstream feeder line 82 and the downstream feeder line 83, and is supplied to the trains running on each feeder line. Here, the train repeats three states: forward running, elliptical running, and braking, but the power consumption is the highest when the train is running forward. The details are well known and are not directly related to the present invention, so their explanation will be omitted.

As shown in Figure 8 (ta), when the train runs from the upstream feeder line 82 to the downstream feeder line 83, the load flowing through the feeder line, especially when the train is running in a row and passes the section 86, is The current changes rapidly in both the upstream feeder wire 82 and the downstream feeder wire 83. Figure 8 (1) shows the situation.
). FIG. 8(b) shows the upstream feeder line 82.
This is a time chart showing the direct current flowing through the downstream open electric wire 83, where the solid line is the load current and the dotted line is the current ΔI that changes according to the load current. When the train passes through the section 86 in a continuous state, the load current of the upstream feeder line 82 is as shown in Fig. 8 (b).
) as shown in the upstream time chart of
Correspondingly, Δ■ occurs on the negative side. Further, the load current of the downstream opening electric wire 83 increases rapidly as similarly shown in the downstream time chart, and accordingly, a Δ error occurs on the positive side. As mentioned above, the DC current change detection relay operates when the positive side Δ■ exceeds the set value.
In the case of a phenomenon as shown in the downstream time chart of FIG. 8(b), there is a possibility of malfunction. To prevent this, compensation called section compensation is generally performed. An example will be explained below.

When a train in the 1st line passes through a section, the load current of the upstream feeder line 82 increases by utilizing the fact that the load current of the downstream open electric wire 83 increases by the amount that the load current of the upstream feeder line 82 decreases. When the power decreases rapidly, the downstream feeder line 83
Initialize ΔD which occurs according to the load current. In other words, even if the train passes through the section in a running state, the downstream opening Δ■ that occurs at that time is reset, thereby making it possible to prevent the relay from malfunctioning.

(Problem to be Solved by the Invention) As is clear from the above explanation, the malfunction of the downstream opening relay for soil removal when the train passes through the section while the train is moving can be reliably prevented by the section compensation described above. It is.

However, during section compensation, the downstream opening Δ■ is in an initialized state and the electric wire cannot be protected. In other words, even if a short-circuit accident occurs in the downstream feeder line while a train in the active state is passing through a section, it may not be detected.

In the past, train formations were short and the number of trains in operation was small, so the section compensation time was so short that it could be ignored.However, recently, train formations have become longer and the number of trains in operation has increased, and the section compensation time has also become shorter. It has become impossible to ignore.

The above is a major drawback of the conventional current change detection relay, and the reality is that there is no solution yet.

The present invention has been made in view of the above-mentioned circumstances, and provides a DC current change detection device 11 that can accurately detect current changes even when a train is passing through a section in a continuous state. Its main purpose is to provide electrical appliances.

[Structure of the Invention] (Means for Solving the Problems) To explain using FIG. 1, in the present invention, the downstream current detection means 2 and the train load current detection means 3 each input a downstream current 11 and the train load current ■8 are detected sequentially in time series, and the current change detection means 4 detects the current change Δ■.
Detect. Here, the train load current IN is a direct current detected and transmitted on the train side. In this case, the difference between the downstream current I and the train load current 8 is taken, and when this difference current It I14 is positive, the current change ΔI with respect to the difference current is calculated. Furthermore, the determination means 5 determines the current change ΔI
The system is configured to determine the size of the problem and detect short-circuit accidents in feeder lines.

(Function) Therefore, if a short-circuit accident occurs in the downstream feeder line when the train passes through a section while the train is running, the train load handling IH remains almost constant, but the downstream open current I increases significantly. , change amount Δ(It IH) with respect to the difference current
will also increase. As a result, short circuit accidents can be detected correctly. In addition, if a short circuit accident does not occur, the magnitude of the downstream current ■ is almost equal to the train load current IF4,
I.

IH remains almost zero, and the change in the difference current is Δ(1
, -IH) do not change, it is also possible to reliably prevent malfunctions when passing through a section.

(Example) Examples will be described below with reference to the drawings.

FIG. 1 is a functional block diagram of an embodiment of a direct current change detection relay (hereinafter referred to as a relay) according to the present invention. In FIG. 1, 1 is a relay, and downstream current detection means 2
It consists of a train load detection means 3, a current change detection means 4, and a determination means 5.

The downstream detection means 2 samples the DC current flowing through the downstream open wire at a predetermined timing, and stores these time-series data. Further, the train load detection means 3 samples the DC current consumed by the train at a predetermined timing, and stores the time series data transmitted by the transmission means.

Here, the method of sampling the current at a predetermined timing and transmitting it using a transmission means is already known (for example, V!
No. 5-74956), so it will be omitted here.

The current change detection means 4 receives a downstream open current I input from the downstream current detection means 2 and the train load current detection means 3,
Calculate the difference in train load current IM (1l-IH), and when this calculated fM I L I H is positive, calculate the current change Δ■. When the determination means 5 determines that the current change Δ has exceeded a predetermined value, it considers that a short-circuit accident has occurred in the feeder line and outputs a relay operation. It is a configuration example diagram.

In FIG. 2, the same parts as those shown in FIG.

6 is a DC current transformer that converts the current flowing to the downstream feeder line;
7 is a DC current transformer that converts the current consumed by the train. The relay 1 has the configuration shown below. That is,
an isolation circuit 8 that electrically isolates the system side and the detector side;
an analog input section that converts the quantity of electricity input from the insulation circuit 8 into an arithmetic value by analog-to-digital conversion;
A digital calculation unit composed of a microcomputer, etc.
cpu ) io, data memory (RAM) 11 for storing input data, and program memory (RO) 4) 12 for storing calculation programs.
, a setting circuit 13 for setting a setting value necessary for detection determination, and an output section 14 for outputting a detection result, and these are connected to each other via an internal bus 15.

Further, 16 is a transmitter for transmitting the train load current detected by the DC transformer 7 in the train to m electric appliances 1, 17 is a receiver for receiving transmission data, and 18 is a transmission means.

In the above configuration, the direct current flowing through the downstream open electric wire 83 and the direct current consumed by the train are converted by the direct current transformers 6 and 7, respectively, and input into the insulation circuit 8. The amount of electricity outputted from the insulating circuit 8 is converted into an analog/digital signal by an analog input section 9, and subjected to arithmetic processing in a digital arithmetic section 10. Digital operation section 1
0 compares the result of the arithmetic processing with the setting value from the setting circuit 13, and outputs it to the output section 14 when the former exceeds the latter.

In this case, the digital calculation unit 10 performs calculations in synchronization with each time the analog input unit 9 samples the quantity of electricity.

FIG. 3 is a flowchart for the arithmetic processing of the digital processing section 10. In FIG. 3, in step S31, the downstream open feeder current ■1 is input. Next step S32
Input the train load current IN to .

In step 833, step S31 and step S32
The difference current It_IN is calculated from each current input in step S34, and the process is moved to the next step.
The sign of I-IH calculated in step 333 is determined. If positive, the process moves to step 335, and if not, the process returns to step S31. In step S35, the difference current I calculated in step S33.

■ Calculate the change Δ(I IM) with respect to.

H [Next, in step S36, the change amount Δ(I −1) calculated in step S35 is compared with a predetermined value IK7. If the former is larger than the latter, the process moves to step 337, and if it is smaller If so, the process returns to step 831. In step 337, a relay operation is output, and the process returns to step S31 to repeat the above process.

The above is an explanation of the processing outline. Next, the algorithm for detecting the DC current change is described in (1) below.
, (2), and will be explained in more detail using the flowchart of FIG.

Δ l =<I − J )(1
−Δt,/1d)n n n-1 ・・・・・・(1) J +Δ■ Δt/ld ・・・・・・(2)n
-1n J.

However, ΔI: ■ 20J: Current change at sample/ring point a Sample 1 Instantaneous value of current at ring point a Instantaneous value of weighted current at sampling point a J: Weight at sampling point n-1 - 1 Instantaneous value of the current Δt: Sampling period td: Time constant Since the above equations (1) and (2) are well-known techniques, detailed explanations will be omitted here, but J is the seventh Δ■ means the instantaneous value of the charging voltage of capacitor C shown in figure (a). means the voltage across the resistor R, that is, the voltage corresponding to the current change.

First, in step 341, the load power? The LIn is read and the process moves to step 842. In step S42, the changed current ΔI is calculated, and in step 843, the instantaneous value J of the current is calculated. Calculate. Next, Stella 7S44 compares the changed current ΔI with the set value ko to determine relay operation. As a result, if ΔIn>ko, the process moves to step S45, and the operational output is derived. Also, ΔIn < k
If o, the process is returned to Stella 7S41 and the above-mentioned processes are repeated.

FIG. 5 shows waveforms showing the actual response of this embodiment, where fa) is the waveform of the downstream feeder current ■ inputted in step S31, and (b) is the waveform of the train load current IN inputted in step S32. The waveform fc) is the waveform of the difference current IL IN calculated in step 333, and (d) is the waveform of the change Δ(I, -IH> calculated in step 835. In addition, each waveform changes at time tQ. This is a diagram when the train passes through the section and enters the downstream open wire.The solid line is the normal state, and the dotted line is the waveform that shows the situation where a short circuit accident occurred on the downstream open wire when the train passed the section. As can be seen from Figure 5(d), under normal conditions Δ<It IN > remains at zero and the relay does not malfunction, but if a short circuit occurs while the train is passing through a section, Δ( 1-
When I) increases and becomes 0, which is greater than a predetermined value IK, relay operation occurs.

As described above, according to the present invention, even if a short-circuit accident occurs in the downstream feeder line when a train passes through a section in a running state, it is possible to correctly determine the accident. In addition, this embodiment can correctly detect short MI accidents in electric wires even when the train is not passing through the section, and can also reliably prevent malfunctions even when the train passes through the section without any reporting accidents. can.

FIG. 6 is a flowchart showing the processing contents of another embodiment.

In this embodiment, the change in the downstream feeder wire ■ is Δ■.

, and the value multiplied by the train negative 7tr current IN, and calculate Δ
This method is characterized by detecting the magnitude of I-KIH. Therefore, in step S63, the change Δ■ in the DC current I of the downstream feeder inputted in step 331 is calculated, and in Stella 7S64, the change ΔI calculated in step 863 and Stella 7S
The difference between the input train load current IH and the value multiplied by 32 is calculated. Here, the value of K is a value commensurate with the gain in calculation of the change amount ΔI as an arithmetic compensation coefficient. Next, in step 365, the value ΔI calculated in step S64
-KIH and predetermined value■.

Compare and judge. As a result, this embodiment can achieve the same effects as the embodiments described so far.

Although the above description has been made regarding a digital type direct current change detection relay, it is clear that the present invention is applicable not only to a digital type but also to an analog type.

[Effects of the Invention] As explained above, according to the present invention, the train load current is compensated for the direct current flowing in the feeder line on the downstream side, so that the train can pass through the section while powering. This makes it possible to reliably detect short-circuit accidents on the downstream side even when the relay is in use, and prevents malfunctions of relays. Furthermore, it can be applied to a DC main power system where many trains are operated and long trains are operated.

[Brief explanation of drawings]

Fig. 1 is a functional block diagram of an embodiment of the DC current change detection relay according to the present invention, Fig. 2 shows the concrete structure of the relay, Fig. 3 is a flowchart showing the processing of the digital calculation section, and Fig. 4 is Flowchart 1 showing the specific processing content for detecting a change in DC current, Fig. 5 is a flowchart showing the processing content of another embodiment, Fig. 6 is a diagram showing the actual response waveform, Fig. 7 1 is a principle diagram explaining the prior art, and 2 is a diagram showing the response of the prior art. 1... DC current change detection #lj8 electric appliance 2... Downstream current detection means 3... Train load current detection means 4... Current change detection means 5... Judgment means FIG.

Claims (1)

[Claims] A digital DC current change detection relay equipped with a current change detection function for inputting a DC current from a downstream DC feeding system and detecting a change in the DC current,
A DC current variation component that inputs a train load current and outputs an operational output when a variation in difference between the DC current of the downstream feeding system and the train load current exceeds a predetermined value. Detection relay.