JPS6142221A - 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 invention] The present invention relates to a protective relay device.

[Technical background of the invention and its problems] In general, there are two parallel circuit transmission lines with one resistance grounding system (hereinafter referred to as -1-position system transmission lines) and ultra-high voltage directly grounding system transmission lines (hereinafter referred to as 1-subsystem transmission lines). When two power transmission lines (referred to as power transmission lines) are installed on the same tower, a zero-sequence circulating current always flows through the lower power transmission line due to induction from the upper power transmission line.

When a one-wire ground fault occurs in such a lower power transmission line, the fault current 21 is limited by the ground resistance and is small, so it is difficult to distinguish it from a phase circulating current.

Therefore, in many cases, it is not possible to determine internal or external faults with ordinary ground fault direction relays that identify direction based on zero-sequence voltage or neutral point current.

A method has been proposed in which the difference current between line 1 and line 2 before the failure is stored as a pair of whistles, and ground fault direction system determination is made in response to the effective amount of change with respect to this stored value.

There are two types of differential current: one that uses only the zero-phase component and one that takes both each phase and zero-phase components. In both of these methods, the change m before and after failure of the effective component with respect to the polarity voltage is used as the operating amount. We are hiring.

On the other hand, a digital relay employing the above method as a line selection relay, that is, a relay that calculates the amount of operation by calculating the above-mentioned contents using a microcomputer is in use. This digital relay has an analog signal processing section that converts the output signal of a current transformer (hereinafter referred to as TC) that detects line current etc. into a digital signal, and the digital signal is sent to a digital signal processing section consisting of a microcomputer. I am typing.

There are various inspection details for this digital relay, but for example, when inspecting the analog signal processing section, it is checked whether or not a signal corresponding to this Ti current is applied to the digital signal processing section when a predetermined inspection current is passed here. I've confirmed it. In this case, the inspection current value is stored in the storage means of the digital bundle processing section as the line current before the failure. Further, this stored value will be compared with the line current after the inspection is canceled.

Therefore, if a ground fault occurs during an inspection, but this fault continues even after the inspection is canceled, the line selection relay may operate erroneously depending on how strong the inspection current is.

In other words, in a conventional protective relay device that takes measures against zero-phase circulating current and has a line selection function, there is a risk that an unnecessary response will occur after the inspection is canceled.

[One object of the invention] Since the present invention was made to eliminate the drawbacks listed in L,
To provide a protective relay device that can reliably prevent unnecessary responses after a safety inspection is canceled even if a system accident occurs during an inspection.

(R essential point of the invention) In order to achieve this object, the present invention samples and holds the voltage and current of the system including the line to be protected, the voltage for detecting the current, and the output of the current detection section at a predetermined period, and also measures the hold value. and an analog signal processing unit that converts the signal into a digital signal.Based on the output of this analog signal processing unit, it detects ground faults in the system, calculates the effective portion of the zero-sequence current of the line to be protected, and detects ground faults. An operation signal that stores the effective part of the zero-sequence current at the time of detection, and compares the calculated value and the stored value of the effective part of this zero-sequence current, and when the deviation exceeds a predetermined value, opens the IC and breaker. an inspection section that outputs signals corresponding to the voltage and current detection section to the analog signal processing section instead of the voltage and current detection section according to an inspection command; The present invention is characterized by comprising a locking means for locking the storage state of the effective portion of the zero-sequence current in the digital signal processing section while a signal is being applied to the signal processing section.

[Embodiments of the invention]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In FIG. 1, the bus 1 has the transmission ff1i to be protected.
Lines 2.3 are connected via circuit breakers 4, 5, respectively. In this case, the power transmission lines 21 and 3 are installed on the same tower as an upper power transmission line (not shown), and a zero-phase circulating current of 1°0 flows therethrough.

Transducers 6, 7 are used to detect the current in this transmission line 2.3.
However, a converter 8 is provided to detect the electric FX connection of the busbar, that is, the power grid, and the secondary side of A is an analog signal! ! ! ! It is connected to the push part 10.

The analog signal processing unit 10 includes a human power converter 11 that converts input voltage and current detection values to predetermined levels, a ripple hold circuit 12 that ripples and holds the converted signal at regular time intervals, and a It is composed of a Δ/[) converter 13 that converts the value into a digital signal.

In addition, in order to detect a ground fault in the system based on the output signal of the analog signal processing section 10 and to detect the direction of a ground fault, a digital signal processing section 20 configured with a microcomputer is installed. The setup number is blank.

The current storage means 21 constituting the digital signal processing section 20 calculates the difference between the zero-sequence current signals A1 and A2 converted into digital signals by the analog signal processing section 10, and also stores the difference, that is, the current value of the zero-sequence difference current. Fixed time TH
It's something to remember.

In addition, the effective component calculation means 22 calculates the zero-sequence difference current signal B1 stored in the current storage means 21 and the pole +Ii voltage created by each phase voltage △3 (for example, in the case of an R-phase one-line ground fault, a ground fault ST phase-to-phase voltage v8□) signal B that does not change by only
2, the effective portion PH of the zero-sequence current is calculated using the following equation.

・I −cosθH...(1) PH=VS■90° OH However, VST<g()6: IH pressure 'OH' Value before storage period of zero-sequence difference current θH: VST<
The phase angle is 90° and 'ON.

The accident detection means 23 uses the zero-phase voltage signal A4 outputted from the analog signal processing section 10 to perform the calculation of the following equation to detect a ground fault.

IVo I≧■, ・・・・・・・・・
...(2) I[dashi, 1vo1: Zero-sequence voltage VK z This is the reference value set for earth fault detection.

Further, the effective part storage means 24 is for holding the derivation value C of the effective part calculation means 22 when the fault detecting means 23 detects a ground fault J.

Furthermore, the ground fault system direction detection means 25 detects the zero-phase current signal A
I, A2 and each phase voltage signal A3 are used to determine whether or not the direction is in the protection direction.

In this case, the motion JiPo is calculated using the following equation.

PO=vS[<906 0 −I −CO2O3·−(3) Next, this operation ff1P. When the effective part PH held in the effective part storage means has the following relationship, the operation signal F is output.

Po−PH≧P8 ・・・・・・・・・
(4) However, P8 is a reference value set for direction determination.

Further, the logical judgment means 26 performs a predetermined logical judgment and outputs an opening command G to the circuit breaker 4.5.

Next, an inspection section 30 is provided to inspect the analog signal processing section 10 and digital signal processing section 20 described above. This inspection section 30 includes an inspection control means 31 activated by an inspection command H, and generates signals corresponding to the outputs of the current transformer 6.7 and the transformer 8 according to a control signal J of this inspection control means. Current transformers 6 and 7 and transformer 8
Instead, the output of the inspection power supply is sent to the analog signal processing unit 10.
It is comprised of a changeover switch 33 that switches the input to the output.

Further, while the inspection signal is being applied to the analog signal processing unit 10 by the processing signal K output from the inspection control unit 31 of the inspection unit 30, the current storage unit 21 and the effective component calculation unit 22 of the digital signal processing unit 20 , effective storage means 2
4. Ground fault system direction detection means 25J3 and logic judgment means 2
6 is processed by 1.

In this embodiment, the digital signal processing section 20, the inspection Hi control means 31 of the inspection section, and the locking means 40 are constituted by a microphone 1"-" microcoater. Explain how it works.

First, when the device is started in step 201, an inspection start command is input to the device in step 202, and it is determined whether or not C is present. An inspection section ITd32 is connected to the analog signal processing section 10 instead of the device 8. In normal times when there is no inspection start command, the current transformers 6 and 7 and the transformer 8 are connected to the ablog signal processing section 10 in step 204.

Next, the subsystem 205 receives a zero-phase voltage signal V input from the grid or the inspection power supply 32. , zero-phase current signal 1 and each phase voltage V, V, V, constant Q
Sample and hold is performed at the cycle of R3, and the hold value is converted into a digital signal. In addition, it is determined in step 206 whether or not the inspection is in progress, and if the inspection is in progress, the process does not proceed to the process in step 207, that is, the line selection protection process, and the process returns to step 20.
Return to 5. If the inspection is not in progress, step 20
Zero-phase voltage signal ■ at 7. A ground fault is detected by calculating the above equation (2) using the digitalized zero-phase voltage signal A4 corresponding to .

Subsequently, in step 208, the result of step 207 is determined, and if it is determined that there is no system fault, the process proceeds to step 209, where the digitized zero-sequence current signals A2 to A2 corresponding to the zero-sequence current signal Io are Memorize A3. This stored value is I. Let it be H.

Then, in step 210, the zero-sequence current value stored in the previous step 209 for a certain period of time and the polarity voltage vs.
In the case of a phase fault), the above equation (1) is calculated to determine the effective amount. Further, in step 211, the effective amount is stored and the process returns to step 205.

Therefore, if there is no accident in the C system, the above steps are repeated at regular intervals.

- h, if an accident is detected in step 208, proceed to slap 212, and calculate the current value of the zero-sequence current signal 1°, etc.
The effective part of the polarity voltage is calculated, and the step 213 uses the calculation result of step 212 and the value stored in step 211 to perform the bell performance in equation (4). The direction of the ground fault is determined based on the result, and if it is determined that the decimal direction of the ground fault is the protection direction and is in operation, the process proceeds to step 215, where a logical decision is made for tripping the breaker. In addition,
This logical judgment refers to, for example, a judgment as to whether or not the usage conditions of the device are met, and whether or not a short-circuit accident has been detected.

Subsequently, in response to the above logical judgment, the summation tube 216 determines whether or not to output a cutoff command to the breaker. If the conditions are met, the process proceeds to step 217, where a breaker tripping command G is output to open the breaker. The protective operation is thus completed.

-, if it is determined in step 214 that it is not working, d
3 and if it is determined that the condition is not satisfied in step 216, the breaker trip command G is not issued and the process proceeds to step 205.
Return to Hereinafter, the operation described above (above) is repeated.

FIG. 3 is a time chart for explaining the detailed operation when an inspection command is given, and (a) shows the inspection command H1 and (b) shows the zero-phase voltage V. , IoT diagram (c) shows the normal zero-sequence current I and the inspection current I. 1 and zero-sequence current I caused by a ground fault. 2. In the same figure (d) t, turn the lock function to the right
The effective component PH of the zero-sequence current of Togi and the effective component of the zero-sequence current when there is no lock function []', (e) in the same figure are calculated by formula (3) when the lock function is right-handed. The amount of movement and the amount of movement without the 1-1 check function, the same figure (
f) is determined by equation (4).P-PH1 (g) of the same figure shows the operating output.

In FIG. 3, before the time L when the inspection command H is given, the zero-sequence current I is normal. is flowing, and at this time t. When the inspection command 1 (can be given), the effective part PM of the zero-sequence current at this point in time is stored and indicates approximately -i lif+.

Next, an inspection current of 1゜1〈〉Io) is applied at time 12, and when a ground fault occurs at time 12, it is opened at a predetermined time (pu ν
('7: The phase lightning 11Vo is emitted, and furthermore, a zero-sequence current of 1°2 flows.

Continued - r, l! ;'If you cancel the inspection at 13:00,
5 at this time? , (The performance Q of the motion fl hip p. is performed.

is the deviation between the effective part PH of the zero-sequence current stored in (inspection command B) and the effective part at the present time, that is, the operation n1). Before t3, the negative OOH constant 1&j is reduced, and after time +3, 1lTj(!-
As shown, 11C1 of 1)-l)H is set for JJJ, Moto (mePs! Kotoki motion f'
1! 8shi; 1 is rolled.

On the other hand, if the memory function is not activated during inspection, the effective portion P8' of the zero-sequence current is the inspection current I. In response to 1, he showed a relatively large number 4, so []. '-PH' takes a negative value immediately after the inspection is canceled. Therefore, a malfunction may occur immediately after the inspection is completed.

On the other hand, in this embodiment, the zero-phase f! Since the memorized state of the effective part of current i is locked, the inspection current I during inspection. Therefore, the operating output is output immediately after the inspection release contact, indicating normal operation.

In the above embodiment, the locking function is activated during inspection, but even if the locking function is activated only during the time when the inspection current is supplied, the same accident detection as described above is possible.

In addition, although the above actual MfIs uses zero-sequence current, if a change in circulating current occurs due to an open phase after a failure in the upper system transmission line, an unnecessary response may occur in the calculation of equation (4) above. The following equation has been proposed to solve this problem.

however, I2: Negative sequence current 1o: Zero-sequence current Ko: A constant determined by the composition of iron 1.

Further, the constant KN is usually determined by the following formula.

It's IS, 12th' constant negative phase circulating current 'Otr,' constant zero-phase circulation'ri flow Guaru.

Note that I is the effective current, 11□ is the effective current a certain time before the current moment, and J and J mentioned above are
Corresponds to 0H. In addition, 1 is 12-1 in the case of an R-phase accident.
+a I +al■, and each phase current RS 1.1.11 is required. The same is true for the S phase of Haku, - ``S phase ts''.

Here, the negative sequence current 12 at the time of a one-wire ground fault is the fault current I.

Since it is equal to [, the following equation holds true.

1-.

='0f-KH'Of '2th 'H' Kanohha1-
,, 1 -
1] 1-I. t-ll8・・・・・・
(7) That is, the effective current 11 is the fault current I. , and in <Fi jA difference I. In addition, if K11-ε' 7th '' OLl+te, it is I8-0, but this J I'; .

Therefore, the zero-sequence current 1. io - each phase current instead 1. [
, I, based on the effective current I,.

S' [Ct using H) 1 It goes without saying that the same result as described above can be obtained. The present invention utilizes this effective current 1.1. F
I is called the effective component of the 0 zero-sequence current. (Effects of the Invention) As is clear from the above explanation, the present invention allows the effective storage state of the zero-sequence current of the digital signal processing section to be changed to 1. Therefore, we provide a highly viscous protective relay device that will not react after inspection and cancellation.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of an embodiment of the present invention, Fig. 2 is a diagram for explaining the operation of the embodiment, and Fig. 3 is a diagram for explaining the operation of the embodiment. This is a time chart. 1... Bus bar, 2, 3... Transmission line, 4, 5... Breaker, 6.7... Current transformer, 8... Transformer, 10...
・Analog Shintan & i, 20...Digital signal processing section, 30...Inspection section, ZIO...Lock means. Applicant's agent Kiyoshi Inomata Figure 1 Figure 3

Claims (1)

[Claims] Voltage for detecting the voltage and current of a system including the line to be protected;
an analog signal processing section that samples and holds the output of the current detection section at a predetermined period and converts the hold value into a digital signal; and an analog signal processing section that samples and holds the output of the current detection section at a predetermined period and converts the hold value into a digital signal; Calculates the effective component of the zero-sequence current of the line, stores the effective component of the zero-sequence current at the time of ground fault detection, and calculates the deviation by comparing the calculated value of the effective component of this zero-sequence current with the stored value. a digital signal processing unit that outputs an operating signal to open the breaker when the voltage exceeds a predetermined value; and a digital signal processing unit that outputs an operation signal to open the breaker when A checking section added to the analog signal processing section; and a locking means for locking the storage state of the effective portion of the zero-sequence current of the digital signal processing section while the checking section is applying a signal to the analog signal processing section. A protective relay device characterized by: