JPH065256B2 - Accident point location method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a fault point locating method for locating a fault point in a power system, and more particularly to a fault point locating method for a multi-terminal transmission line.

[Prior art and its problems] In recent years, the demand for power systems has expanded and the area has expanded, and the number of terminals has become longer and more complex. Development of a high accident location device is desired.

Currently used accident location methods are pulse laser method in which an impulse is applied at the time of an accident and the time until the reflected wave returns, or the pulse generated at the accident point is measured at the electrical stations at both ends. However, there is a surge receiving system that locates the accident point from the time difference, and all of them use the traveling wave phenomenon.

However, the applied pulse or accident surge has a high propagation speed, is subject to attenuation / distortion as it progresses, is reflected at a suspension or branch point, or is confused with lightning. However, there is a clear limit in terms of performance improvement.

To improve this, for example, by detecting the current flowing through the overhead ground wire of the overhead power transmission line at a plurality of positions, such as a steel tower,
A method for locating an accident section based on the phase and absolute value information has been proposed. However, this has a drawback that detection is required at a large number of places in order to improve the orientation accuracy, and accordingly a large number of devices are required, which increases the equipment cost.

The object of the present invention is to improve the above-mentioned drawbacks of the prior art.
Accident points can be accurately located even in multi-terminal transmission lines that have multiple system branches and have multiple power sources, and
It is an object of the present invention to provide a new accident point locating method that helps reduce the number of devices and, in addition, the equipment cost and improve reliability and maintainability.

[Summary of the Invention] That is, according to the present invention, in a multi-terminal power transmission line, voltage (V) / current (I) information of each of the three phases measured at each terminal and a section from the terminal to the terminal or a branch point from the terminal. Up to the section (hereinafter referred to as section), the fault section discriminant function f (V, I,) defined for each section from the section distance () and the line impedance (Z) that are predetermined.
Z) is used to sequentially proceed from the peripheral node to the internal node to locate the faulty section, and then it is determined from the voltage (V) / current (I) information of each of the three phases measured at the terminals. It is characterized in that a fault point is located based on voltage (V) / current (I) information at both ends of the fault section, a section distance () and a line impedance (Z) which are predetermined for the fault section.

[Examples] Examples of the present invention will be described in detail below.

In FIG. 1, the accident point is F, and the distance between the terminals SR is k (0 <k <
Assuming 1) and the positive phase impedance per unit length of the transmission line is Z ₁ , for example, when an interphase short circuit accident occurs in the b and c phases, the terminal S V _b , V _c ... Phase voltage of b and c phases at terminal S I _b , I _b ... Phase current of b and c phases at terminal S Z _bcF ... Can be expressed as impedance at _fault point. When Z _bcF is so small that it can be ignored, the distance k to the accident point is defined by equation (1), which is the basic equation of the current distance relay. On the other hand, the terminal R is also equation (1). Since the same relational expression as is _established , Z _bcF, which can be an unknown number in general, can be eliminated,
After all Vb ', Vc' ... Phase voltage of b and c phases at terminal R Ib ', Ib' ... Phase current of b and c phases at terminal R The coefficient k is obtained. That is, it can be known in advance,
The fault point can be located based on the current / voltage information measured at each point of Z _{1 and} terminals S and R. The basis of the present invention is to extend this matter to a general multi-terminal transmission line.

As shown in FIG. 2, in a three-terminal power transmission line having terminals S, T, and R, a node N is set, and section distances of the sections SN, TN, and RN are ₁ , ₂ , ₃ and sections SN, T, respectively.
Positive phase impedances per unit length at N and RN are Z ₁ ^SN , Z ₁ ^TN , and Z ₁ ^RN , respectively. As in the case of the above-mentioned two terminals, a phase-to-phase short circuit accident occurs in the b and c phases and the accident point
Is in the interval RN. The distance from the node N to the accident point F is k1 ₃ . According to the equation (2), k is represented by the following equation.

V _b ^N , V _c ^N ... Phase voltage of b and c phases at node N I _b ^N , I _c ^N ... Phase current of b and c phases at node N On the other hand, according to Kirchhoff's law, Is. By substituting Eqs. (4) and (5) into Eq. (3), the following equation is obtained.

That is, if the section distances of the sections SN, TN, and RN and the positive-phase impedance per unit length are known, the fault point is located by the voltage / current information measured at the points of the three terminals S and R. .

The present invention, prior to the location of the accident point by the formula (6),
This is a method of locating an accident section by using an accident section discriminant function f. The orientation of this accident section will be described below.

Consider the accident section discriminant function f _ST given by the following equation for the section RT.

Similarly for sections TR and SR think of. When an accident occurs in the section RN and the sections SN and TN are sound, f _ST = 0, f _TR ≠ 0, f _SR ≠ 0 (10). Therefore, from the measured values of the voltage / current information at each terminal, S, T, and R, the fault segment discriminant function f can be used to locate the fault segment as follows.

f _ST = 0, f _RT = 0, f _SR = 0 → no accident f _ST = 0, f _RT ≠ 0, f _SR ≠ 0 → accident section RN f _ST ≠ 0, f _TR ≠ 0, f _SR = 0 → Accident section TN (11) f _ST ≠ 0, f _TR = 0, f _SR ≠ 0 → Accident section SN And even in a multi-terminal transmission line with 4 or more terminals, it is possible to locate the accident section and the accident point by the same procedure. Is. For example, in a power transmission line of the system shown in FIG. 3, section AN ₁ for node N ₁ by applying fault section discriminant function described above with respect to the node N ₁ and N _2,
For B ₁ , CN ₁ , and node N _2, it is determined which of the sections DN ₂ and EN ₂ contains the accident point. As a result of the judgment, when the accident point is not included in any of these sections, the voltage / current information of the nodes N ₁ and N ₂ is stored in the accident section discriminant function f (V, I, Z) = 0. Since it can be represented by using the voltage / current information of the terminals A, B, and C and the voltage / current information of the terminals D and E, respectively, the nodes N ₁ and N ₂ and the terminal H whose branch points are the node N ₃ are eventually used. It can be replaced with a configured terminal transmission line, and
The same procedure as in the case of the terminal transmission line can be applied.
That is, even in general transmission lines of complicated and diverse systems, if the operation is performed from the surrounding nodes by the accident section discriminant function f, and the operation is sequentially advanced to the internal nodes, finally the accident section and the accident will occur. Orientation of points is possible.

In the above explanation, the interphase short circuit accident of the b and c phases is taken as an example.
Needless to say, the present invention is not limited to this and can be applied to a ground fault accident.

Next, an example of a specific configuration for carrying out the present invention will be described with reference to the drawings. FIG. 4 is a block diagram thereof. The transformers 2, 2 ', 2 "are respectively connected to the terminals of the sections 1, 1', 1" of the transmission line branched at the node N by the sampling circuits 3, 3 ', 3 "and the transceivers 4, 4'. , 4 ″ are sequentially arranged and connected. The transmitters / receivers 4, 4 ′, 4 ″ are connected to each other by, for example, an optical fiber of an optical composite overhead ground wire or a transmission line 5, 5 ′, 5 ″ of a microwave line.
The voltage / current information of each terminal observed at 2 ', 2 "is information synchronized with sampling at the sampling circuits 3, 3', 3". The terminal of the section 1 is a higher terminal than the terminals of the other sections 1'and 1 ", and the arithmetic processing for locating the fault point is performed here. The voltage / current information of each terminal of the sections 1'and 1 "is received from the devices 4'and 4" via the transmission lines 5'and 5 ", and the fault point locating device 6 performs arithmetic processing to determine the fault point. The display 7 displays the result. Incidentally, the transmission lines 5, 5 ', 5 "are used not only for transmission of voltage / current information but also for transmission of a synchronizing signal for synchronizing the information signal of each terminal of each section 1, 1', 1". It does not prevent sharing with other communication lines.

FIG. 5 is a calculation flowchart of the accident point locating device 6.
If an abnormal value is confirmed in the voltage / current information from each terminal of each section 1, 1 ′, 1 ″, the accident occurrence / non-existence judging unit 61 notifies the occurrence of the accident, and informs the accident form judging unit 62 of the voltage / current information. The accident type determination unit 62 determines the type of accident, that is, the phase short circuit accident and the ground fault, and
The voltage / current information of each phase at each terminal is used. When the accident type is determined, the accident section locating unit 63 performs the calculation by the above-described accident section discriminant function f to locate the accident section. The accident section discriminant function f is variously set according to the difference in the accident form. The accident point locator 64 performs accident point locating for the accident section. The section distances of sections 1, 1 ', and 1 "and the positive-phase impedance per unit length are input in advance as known values. And each section 1,
The fault point is located by using the voltage / current information of each terminal of 1'and 1 ".

The result of orientation by the accident point locating device 6 is displayed on the display device 7, for example, about the time when the accident occurred, the accident section, and the accident point.

Since the present invention uses the voltage / current information of each of the three phases measured at each terminal of the multi-terminal transmission line as an element of fault location,
In particular, if attention is paid to this instantaneous current value, it is possible to have a function as a system protective relay system using a current differential relay.

[Effects of the Invention] As described above, according to the present invention, voltage / current information of each terminal of a multi-terminal transmission line, for example, three-phase each phase measured at a substation, and a section from a terminal to a terminal or a branch from the terminal. Voltage and current information is calculated at each terminal because the fault point is located by the fault zone discriminant function using the predetermined zone distance and line impedance for the zone up to the point It can be configured with only a device that measures and transmits to the upper terminal and a device that performs arithmetic processing at the upper terminal, which is inexpensive without compromising accuracy compared to the conventional orientation method by installing many towers. .

In addition, various devices necessary for carrying out the present invention are only installed in each terminal, which is very advantageous in terms of reliability and maintainability.

[Brief description of drawings]

Figures 1, 2 and 3 show 2-terminal transmission lines and 3 respectively.
FIG. 4 is a system diagram of the terminal transmission line and the 6-terminal transmission line, FIG. 4 is a configuration diagram according to the embodiment of the present invention, and FIG. 5 is a calculation flow diagram of the accident point locating device 6. 2 ... Transformer, 3 ... Sampling circuit, 4 ... Transceiver, 6 ... Accident point locating device, 7 ... Indicator, 61 ... Accident occurrence determination unit, 62 ... Accident form determination unit, 63 ... Accident section locating unit, 64 … Accident point locator.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Kawakami 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki Hitachi Cable Co., Ltd. Electric Wire Laboratory (56) Reference JP-A-58-219463 (JP, A) ) JP-A-58-208675 (JP, A)

Claims (1)

[Claims] 1. In a multi-terminal transmission line, voltage (V) / current (I) information of each of the three phases measured at each terminal and a section from a terminal to a terminal or a section from a terminal to a branch point (hereinafter referred to as a section) The fault section discriminant function f (V, I, Z) defined for each section from the section distance () and the line impedance (Z) that are predetermined for
When the accident point is included in the section f (V, I, Z) ≠ 0
If the accident point is not included, f (V, I ,,
Z) = 0 is used to determine from the nodes around the multi-terminal transmission line by the accident section discriminant function f, and when the accident point is not included, the determination is sequentially advanced to the internal nodes. After locating the faulty section, the voltage (V) and current (I) of each of the three phases measured at the terminals
A feature of the present invention is to locate a fault point from voltage (V) / current (I) information at both ends of the fault section determined from information, and a section distance () and line impedance (Z) that are predetermined for the fault section. Accident point location method.