JPH0758305B2 - Fault location method - Google Patents

Description

Detailed Description of the Invention TECHNICAL FIELD OF THE INVENTION

In order to secure the reliability of the power supply, the present invention locates the fault position on the transmission line based on the voltage amount and the current amount of each phase after the accident detected at both ends of the transmission line, thereby promptly recovering the fault. It relates to a fault location method that aims to improve the quality.

2. Prior Art and its Problems When a failure occurs in a system in which two electric stations A and B are at both terminals as shown in FIG. 5, it is necessary to know the distance from the A or B terminal to the failure point F. Is necessary and indispensable for the subsequent repair work of the defective portion. For this reason, in addition to the surge reception system and the pulse radar system, there is a system that does not require a special device, and measures the impedance using voltage and current at the time of system failure to find the failure point. Assuming that the state shown in FIG. 6 at the time of failure, the failure point resistance R _F due to an arc or the like exists at the failure point _F. In the following description, all electric quantities are vector quantities unless otherwise stated. In FIG. 6, failure point F
The fault currents I ^A and I ^B that flow from both terminals A and B will flow to this pin. Here, if the relationship between the voltage and the current at the A terminal is expressed by an equation, V ^A = Z _A · I ^A + R _F (I ^A + I ^B ) ... (1) However, Z _A indicates the impedance from the A terminal to the failure point F. From this equation (1), the system impedance Z at the time of a failure seen from the A terminal is In addition to impedance Z _A The term of comes in and contains an error. If is a pure resistance component, by separating only the reactance component of the fault point resistance R _F , the distance to the fault point F can be measured from the point where the reactance is proportional to the distance. Impedance feature of B terminal side because it contains I ^B is to cause handling can not be error as resistance component Different and terminal A to. In the actual case, it is unlikely that the phases of I ^A and I ^B will match, and it is difficult to correct the error. Japanese Unexamined Patent Publication No. 58-174863 has been proposed as a method that does not cause an error such as the second term in the equation (2). In this system, terminal devices A1 and B1 are provided at terminals A and B as shown in FIG. 5, and the voltage amount and current amount measured by the terminal devices A1 and B1 are transmitted to the central device C as data, In C, the position of the fault point is located by vector operation according to a predetermined orientation calculation formula using the data from each terminal. However, since this method obtains the orientation calculation formula by the symmetric coordinate method, it is premised that each phase has the same condition. However, in an actual transmission system, each phase cannot be in the same condition, and therefore when it is applied to an actual transmission system, high orientation accuracy may be insufficient in some cases.

[Object of the Invention]

In view of the above, the present invention provides a fault point locating method based on a measurement method that does not cause an error such as the second term in the above equation (2) to further improve the locating accuracy and change the parameters of the locating calculation equation to determine the fault type. An object of the present invention is to provide a fault point locating method capable of locating without changing the locating calculation formula depending on the failure phase.

[Points of the Invention]

The gist of the present invention is that in a transmission line system consisting of two terminals,
The voltage of each phase of both terminals by terminal equipment installed at both terminals,
After sampling the current, collecting the sampling data of both terminal devices in one place and synchronizing each data, for each phase, the self-phase voltage value measured at its own terminal was measured at the other terminal. Subtract the phase voltage value, and then add the product of the distance between both terminals and the voltage drop per unit length of the own phase due to each phase current measured at the other terminals and measure the value at the own terminal and the other terminal. The distance from the self-terminal to the fault point is calculated for each phase by dividing by the sum of the voltage drop per unit length of the self phase based on the current value of each phase.

Examples of the invention

FIG. 2 shows an equivalent circuit per unit length of each phase of the asymmetric three-phase circuit in the second terminal system one line, where Z _aa ,
Z _bb and Z _cc are self-impedance of each phase per unit length,
Z _ab , Z _bc , and Z _ca indicate the in-line mutual impedance per unit length between ab phases, bc phases, and ca phases. here,
The currents flowing in the a, b, and c phases measured at the A and B terminals are I _a ^A ,
If I _b ^A , I _c ^A , I _a ^B , I _b ^B , and I _c ^B , the voltage drop per unit length of each phase from the A and B terminals to the fault point by each current is as follows. Can be expressed as Here, assuming an a-phase one-line ground fault and assuming the fault point resistance to be R _F , the equivalent circuit diagram at that time is as shown in FIG. However, the distance between the A and B terminals is L, and the failure point is a distance αL from the A terminal (where 0 <α <1). Therefore, the distance between the fault point F and the terminals A and B αL, (1-α) L
Can be obtained by dividing the voltage drop from the A and B terminals to the fault point F by the voltage drop per unit length. Since the a-phase voltage V _a ^F at the failure point ^F becomes V _a ^F = R _F (I _a ^A + I _a ^B ) due to the resistance R _{F at the} failure point, letting the A terminal be the measurement point, V _a ^A −αLV _aa ^A ＝ V _a ^F ＝ R _F (I _a ^A ＋ I _a ^B ) …… (5) Letting the B terminal be the measurement point, V _a ^B − (1-α) LV _aa ^B ＝ V _a ^F ＝ R _F (I _a ^A ＋ I _a ^B ) ……
(6) is established. Here, when the fault point resistance R _F = 0, the right side of equations (5) and (6) is “0”, so the distance from the A and B terminals to the fault point F αL, (1-α) The orientation calculation formula of L can be expressed as the following formulas, respectively. When a fault point resistance R _F is present against this, since the resistor R _F is not be measured, (5), R _F using the expression (6)
By eliminating, the distance αL from the A and B terminals to the fault point F,
When the orientation calculation formula of (1-α) L is obtained, each can be expressed as the following formulas. The values used in equations (7) to (10) are the voltages and currents measured at the A and B terminals, or the values that can be obtained from these, so the voltages measured at the A and B terminals The fault point can be located by collecting the current values at one place and using them in synchronization. In the case of b-phase and c-phase one-line ground faults, the orientation calculation formula can be similarly obtained. When there is a fault point resistance R _F , in the case of a b-phase 1-wire ground fault, the location calculation formula for the distance αL, (1-α) L from the A and B terminals to the fault point F is expressed as You can Similarly, when there is a fault point resistance R _F , the distance α L, (1-
The orientation calculation formula of α) L can be expressed as the following formula. In this way, the orientations of each orientation equation (9)-(14) are the same,
The fault point of each phase can be located only by changing the parameters. At the time of three-phase short circuit, the orientation values of Eqs. (9), (11) and (13) and the orientation values of Eqs. (10), (12) and (14) become equal. In the case of 2-wire short-circuit or 2-wire ground fault, (9), (1
In the equations (1), (13) and (10), (12), (14), the orientation values of the two fault phases are equal. When there is a one-line ground fault, the orientation formula of the fault phase may be used. That is, it is not necessary to use different orientation formulas depending on the fault type, and various faults can be located by using the fault phase orientation formula. In the case of a three-phase short circuit or a two-wire ground fault, it is possible to use the average value of the failed phases. In the above description, the two-terminal system one line has been described, but the two-terminal system parallel two lines can be handled in the same manner. FIG. 3 shows an equivalent circuit diagram per unit length regarding a phase of an asymmetric three-phase circuit in a two-terminal parallel two-line system. In the figure, Z _aa , Z _bb , and Z _cc are the self-impedances of each phase per unit length of the 1L line, and Z _ab and Z _ca are the ab of the 1L line.
Mutual impedance per unit length between phases, ca phase,
Z _aa ′, Z _ab ′, and Z _ca ′ represent line impedance between the a phase of the 1L line and each phase of the 2L line. In addition, here
In order to explain the a-phase failure of the 1L line, the mutual impedance of other phases and the mutual impedance between lines are omitted. Here, the currents flowing in the a, b, and c phases of the 1L line and the 2L line, which are measured at the A and B terminals, are I _a ^A , I _b ^A , I _c ^A , I _a ^B , I _b ^B , and I, respectively.
_c ^B , I _2a ^A , I _2b ^A , I _2c ^A , I _2a ^B , I _2b ^B , I _2c ^B , the unit length of the 1L line a phase from the A and B terminals to the fault point F due to each current. The voltage drop components V _aa ′ ^A and V _aa ′ ^B can be expressed as follows. The other phases can be similarly expressed. Here, assuming an a-phase 1-line ground fault and assuming the fault point resistance to be R _F , each orientation calculation equation can be expressed as follows, in the same manner as in the above-mentioned two-terminal system one line. First, in the case of the fault point resistance R _F = 0, the orientation calculation formula of the distance αL, (1-α) L from the A and B terminals to the fault point F is the same as the formulas (7) and (8). Can be expressed as When the fault point resistance R _F exists, the orientation calculation formulas for the distances α L, (1-α) L from the A and B terminals to the fault point F are the same as the formulas (9) and (10). It can be expressed as Similarly, for the b-phase and the c-phase, the voltage drop per unit length is calculated in the same manner as in the equation (15), and (16) to (1)
Orientation can be performed by substituting the voltage drops V _aa ′ ^A and V _aa ′ ^B in Eq. 9) for application. Also, in the case of not a 1-wire ground fault but a 2-wire short circuit or a ground fault, according to the present invention, the voltage drop from the measurement terminal of each phase to the fault point is considered, and the voltage drop from the A terminal and the voltage from the B terminal. Since the orientation is performed when the drops are equal at the failure points, the orientation can be performed by applying the orientation calculation formula for each failure phase. For example, as shown in Fig. 4, a, b
Considering the two-wire short circuit of the phase, the voltage drop from the A terminal and the voltage drop from the B terminal are the same at the fault point F for the a phase. Therefore, the orientation can be determined by the equations (18) and (19). ,
The b-phase can be similarly oriented. At this time, each orientation calculation equation locates the same failure point.
Even in the case of a three-phase short circuit, orientation is performed for each of the a-phase, b-phase, and c-phase, so that each orientation calculation expression locates the same fault point. Therefore, in the case of a two-wire short circuit, a ground fault, and a three-phase short circuit, the orientation results are complicated, and they can be displayed individually or averaged.

【The invention's effect】

According to the present invention, the voltage drop from the measurement terminal of each phase to the fault point is considered, the orientation calculation is performed by utilizing the fact that the voltage drop from each terminal is equal at the fault point, and the voltage drop system Since it is configured to use the self-impedance of each phase, the mutual impedance in the line, and the mutual impedance between the lines, there is no error as in the past, and the failure type by changing the parameters of the orientation calculation formula, Depending on the failure phase, orientation can be performed without using another orientation calculation formula.

[Brief description of drawings]

1 is an equivalent circuit diagram in the case of a phase 1 wire ground fault, and FIG. 2 is 2
Equivalent circuit diagram per unit length of each phase of asymmetric three-phase circuit in one line of terminal system, FIG. 3 is an equivalent circuit diagram per unit length of each phase of asymmetric three-phase circuit in two-terminal system parallel two line, FIG. 4 is an explanatory diagram of an a / b phase two-wire short circuit fault, FIG. 5 is a configuration diagram of a two-terminal transmission system, and FIG. 6 is a state explanatory diagram at the time of a failure in the two-terminal transmission system. A1, B1 ... Terminal device, C ... Central device, _Zaa , _Zbb , _Zcc ...
… Self impedance, Z _ab , Z _bc , Z _ca …… In-line mutual impedance, Z _aa ′, Z _ab ′, Z _ca ‘…… Line mutual impedance, L …… AB terminal distance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Mitsuo Saito, No. 1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Fuji Electric Co., Ltd. No. 1 within Fuji Electric Co., Ltd. (56) Reference JP-A-52-40746 (JP, A) JP-A-53-116446 (JP, A) JP-A-58-168976 (JP, A)

Claims (3)

[Claims] 1. In a power transmission system having two terminals, terminal devices installed at both terminals sample the voltage and current of each phase of both terminals, and the sampling data of both terminal devices
After collecting the data at each location and synchronizing each data, subtract the self-phase voltage value measured at the other terminal from the self-phase voltage value measured at the self terminal for each phase, and then the distance between both terminals. And the voltage drop per unit length of the own phase due to each phase current measured at the other terminal, and then adding the product per unit length of the own phase according to each phase current value measured at the own terminal and the other terminal. A fault location method characterized by calculating the distance from its own terminal to the fault point for each phase by dividing by the sum of the voltage drop of. 2. The fault locating method according to claim 1, wherein the system is one line and the voltage drop per unit length is calculated by calculating the self-impedance of the transmission line and the mutual impedance in the line. A fault location method characterized by being used. 3. The fault locating method according to claim 1, wherein the system is operated in parallel with two lines and the voltage drop per unit length is calculated by calculating the self-impedance of the transmission line and the mutual impedance in the line. A fault location method characterized by using the line impedance and line mutual impedance.