TWI493200B - Smart feeder failure sensor system - Google Patents

Description

Intelligent feeder fault detection system and method thereof

The invention relates to feeder fault detection, in particular to a smart feeder fault detection system and method thereof.

A typical feeder circuit transfers power from a power source to a downstream load via a feeder line, passing through several automated switches. An electric raft is installed at a connection point between the power source and the feeder line as an accident protection switch device, and a feeder information end device (ie, FTU) is disposed at each automation switch in the feeder line. Each FTU measures the voltage, current, and the three-phase current and the N-phase current measured by the voltage sensor on the automatic switch and through the comparator and the current comparator. Each FTU is connected to the control center to transmit the detected voltage and current conditions at the automatic switch to the control center, so that the control center can judge the feeding condition of the overall line, and immediately know the fault point when the fault occurs. Overhaul the work.

The most important function in the feeder automation system is Fault Detection Isolation Restoration (FDIR). The feeder information terminal equipment must generate and record the correct fault flag to provide the control center to start FDIR as the judgment feeder. The basis of the accident section.

The fault flag of the feeder information end device in the conventional feeder automation system is generated by using the current rms value. When the FTU is overcurrent cut, the array current value and time value are taken for the three-phase circuit (ABC three-phase set value is the same) At the same time, another array current value and time value are intercepted for the ground overcurrent. These values are compared to the "current-time characteristic curve" of the previously stored and simulated overcurrent, ground overcurrent protection switch. When the continuous calculation of the current rms value is greater than the current value of the analog "current-time characteristic curve" set by the FTU, and the duration also exceeds the time value of the analog "current-time characteristic curve" set by the FTU (the above FTU The current value and time value must be set remotely, and the fault flag of the line is generated.

An example of the function of detecting a fault current and generating a fault flag is described below. At present, the specification uses the current type fault flag to judge (no added voltage judgment factor): step type current-time (4 points or 8 points) fault flag judgment

- Ia Ib Ic Current-Time Fault Current Judgment and Setting

- In current-time fault current judgment and setting

- Provides 8 sets of parameters for CO and LCO TOC curves. I1/T1, I2/T2, I3/T3, I4/T4, I5/T5, I6/T6, I7/T7, I8/T8; current FTU factory setting settings For 4 groups (I1/T1, I3/T3, I5/T5, I7/T7), the values are as follows

However, in practice, the application can be set to 8 groups, and the set value must be different according to the TAP setting value of each feeder, and the curve download function can be executed from the control center to update the parameters in the FTU at any time.

At present, the FTU parameter setting must be set in the first group, and the group position set by other groups can be arbitrarily set. The only thing to note is that the current value of the latter group must be greater than the front, and the time should be reversed. Less than the front.

However, the method used in the prior art has the disadvantage that different current-time characteristic curves are set according to different feeder lines for the current-time characteristic curve, which is often incorrectly set (not based on the reference value of the feeder power supply). ), and because of the different load conditions at the various switches, the FTU of the same feeder does not have a fault flag, and the FDIR of the system cannot determine the correct fault location.

The inventors propose a solution to the problems in the above-mentioned prior art. The design concept of the fault flag generation of the feeder information end device in the feeder automation is a simple setting and is not easy to generate the design of the false signal. That is, when the feeder has a trip, the feeder line must have no load, that is, the current will be Return to zero, at this time, the fault detector determines that there is an accidental trip to generate the fault flag, otherwise it is determined that the interference error number does not raise the flag.

In order to solve the problems encountered in the above-mentioned prior art, the present invention proposes a smart feeder fault detection system and a method thereof, wherein the reference value for comparison is the starting current set by the electric power, and the value is quite stable, so this one The method does not suffer from misjudgment due to changes in the line. According to this, the correct fault flag is generated for the control center to be used as the basis for judging the feeder accident section. Therefore, the control center can know that the section and the phase of the fault occur at the relevant automation switch. The method used in this case is quite simple, its accuracy is high, and the fault signal and control center can be provided immediately, which is not comparable to the above-mentioned conventional techniques.

In order to achieve the above objectives, this case proposes a smart feeder fault detection. The system is used in a feeder circuit, the system includes: four sets of current detectors are arranged in an FTU for detecting currents in three-phase and zero-phase circuits of a feeder circuit; and several digital signal processing a unit, each digital signal processing unit is respectively connected to a corresponding current detector for receiving a current signal of the current detector, and calculating a root mean square value of each period for each phase current; a microprocessor Receiving a signal from the four sets of digital signal processing circuits, that is, a root mean square value of each period of current of each phase; wherein the microprocessor includes a logic processing unit, and the logic processing unit includes fault determination logic; The processor compares the current rms value of each period measured by each phase received with the starting current set by the FTU (reference power), and if the current of the phase is at a preset number of cycles The square root value is greater than a set range of the starting current set by the electric power, and the final current value is zero, indicating that there is an accidental trip and a fault flag is generated; and the fault flag is transmitted to the control center for control. Analyzing the heart as a basis for the feeder section of the accident; the control center can learn the automation of the correlation at the switch, and that segment relative to other failure.

In addition, in the present invention, a smart feeder fault detection method is constructed according to the above system, and the method comprises the steps of: applying four sets of current detectors at one FTU for detecting three-phase and zero-phase circuits of a feeder circuit respectively. Current; after receiving the current signal of the current detector by the four digital signal processing circuits, calculating the root mean square value of each period for the current of each phase; receiving, by a microprocessor, the signal processing circuit from the four groups of digital signals The signal, that is, the root mean square value of each period of the current of each phase; the microprocessor starts the current rms value of each period measured by each phase received and the FTU (reference power) setting Current comparison; if the cycle time is set for several cycles, the current rms value of the phase is greater than a set range of the starting current set by the FTU (reference power), and the final current value is lower than a set minimum current Therefore, when it can be regarded as a power source and no power is supplied to the feeder line, the watch must have an accidental trip to generate a fault flag; And transmitting the fault flag to the control center; for the control center as the basis for judging the feeder accident section; therefore, the control center can know which section and phase failure occurs at the relevant automation switch.

1‧‧‧Power supply

2‧‧‧Automatic switch

3‧‧‧Electricity

10‧‧‧FTU

100‧‧‧ number

20‧‧‧ Current Detector

30‧‧‧Digital signal processing circuit

40‧‧‧Microprocessor

45‧‧‧Logic Processing Unit

46‧‧‧Digital Signal Processing Unit

50‧‧‧Control Center

60‧‧‧ memory

70‧‧‧ display unit

The schematic of Figure 1 shows a feeder circuit.

Figure 2 shows the component blocks and their connections of the smart feeder fault detection system in this case.

Figure 3 shows the relationship between current and time period at the fault node under fault trip conditions.

Figure 4 shows the relationship between current and time period at the fault node under failed input conditions.

Figure 5 shows the flow chart of the smart feeder fault detection method in this case.

Figure 6 shows another type of component block and its connection relationship of the smart feeder fault detection system of the present case.

Figure 7 shows the signal transmission method of the smart feeder fault detection system in this case.

In view of the structural composition of the case, and the functions and advantages that can be produced, in conjunction with the drawings, a preferred embodiment of the present invention is described in detail below.

Referring to FIG. 1, the smart feeder fault detection system of the present invention is used in a feeder circuit, wherein the feeder circuit includes a power source 1 for transmitting power to a downstream load terminal via a feeder line, after several automations. switch 2. Install the electric 驿 3 (which can be CO or LCO) at the connection point between the power supply and the feeder line as a trip feeder. A feeder information end device 10 (i.e., FTU 10) is disposed at each of the automation switches 2. Each feeder line includes a three-phase line with a phase difference of 120 degrees and an N (neutral) phase circuit (not shown). Each FTU is measured by a voltage sensor (not shown) to measure the voltage, current, and through the comparator, the comparator, and the N-phase current through the voltage regulator. Each FTU 10 is coupled to the control center 50 to transmit the detected voltage and current conditions at the automatic switch 2 to the control center 50 to cause the control center 50 to determine the feed status of the overall line, which is instantaneously obtained when the fault occurs. Know the fault point for maintenance work. The system to which this case applies is a single power system, that is, there is only one power supply in a feeder line, as shown in Figure 1, although there are two power sources in the figure, as indicated by the number 100 in Figure 7, this The feeder lines corresponding to the two power sources are not connected.

Please refer to FIG. 2, which shows a block diagram of the device of the present invention and a connection between the components.

In this case, each FTU 10 is configured with: Four sets of current detectors 20 are respectively used to detect currents in the three-phase and zero-phase circuits of a feeder circuit.

Each of the digital signal processing circuits 30 is connected to a corresponding current detector 20 for receiving the current signal of the current detector 20, and calculating the current of each phase for each period. Root mean square value.

A microprocessor 40 receives signals from the four sets of digital signal processing circuits 30, i.e., the root mean square value of each cycle of the current of each phase. The microprocessor 40 includes a logic processing unit 45, which includes the determination logic of the fault in the present case. The microprocessor 40 compares the current rms value of each cycle measured by the received phases with the start current set by the FTU 10. If at the preset number The cycle time (preferably the basic fastest trip time (3Cycle) 50ms), the current rms value of the phase is greater than a set range of the starting current set by the FTU 10, and in another preset cycle After the number, the current value is lower than a set very low current (relative to the normal current, such as 3 amps), so that the system does not provide power to the feeding system, it means there must be an accident jump. Take off and generate a fault flag. The fault flag is transmitted to the control center 50. The control center 50 serves as a basis for judging the feeder accident section. Therefore, the control center 50 can know that the section and the phase of the fault occur at the relevant line switch 2.

If the above conditions are not met, the microprocessor 40 checks that when the phase current values exceed the first set of values of the CO/LCO and continuously exceed a predetermined time (eg, 20 seconds or more), the microprocessor 40 will re-determine. Check that the system power meets the above requirements.

As shown in Figure 7, in an actual system, the signal can be transmitted to the control center via the fiber-to-substation FRTU (substation) of the power network, or wirelessly to FRTU via GPRS. The electric station is then transferred to the control center.

Referring to FIG. 6, in the present case, the four digit signal processing circuit 30 is also integrated with the microprocessor 40, that is, a digital signal processing unit 46 is constructed in the microprocessor 40, and the four groups of current detectors are configured. The measured signal values of 20 can be sent directly to the microprocessor 40, and the digital signal processing unit 46 calculates the rms value of each cycle for the current of each phase. The microprocessor 40 then performs the subsequent operations.

A memory 60 is coupled to the microprocessor 40 for storing the computational programs required in the present case, and memorizing the currents obtained by the phases and their periodic root mean square values, which are stored in a manner corresponding to time. Get up for control Center 50 access is used for later data analysis.

The accidents can be divided into two types: fault trip and input failure. Please refer to Figure 3, fault trip means that if the feeder is in the feed, there is a short circuit fault in the feeder, which will cause the instantaneous current to exceed the rated value, resulting in the current of the phase during the preset number of cycles. The square root value is greater than a set range of the starting current set by the FTU 10, and the final current value is lower than a set minimum low current, so that the system can be determined that the line is faulty when the system does not provide power to the feeding system. Jump off.

Please refer to Figure 4. Input failure means that if the feed current is zero and there is a short-circuit fault on the feeder, the instantaneous current will exceed the rated value, resulting in the current of the phase for a preset number of cycles. The mean square follow-up value is greater than a set range of the starting current set by the FTU 10, and the final current value is lower than a set minimum low current, so that the system does not provide power to the feeding system, then it can be determined that the line occurs. The fault trips.

The present invention further includes a display unit 70 connected to the processor for displaying the processing result of the processor, such as the current of the phase is abnormal.

The smart feeder fault detection method performed by the above device comprises the following steps (please refer to FIG. 5): applying four sets of current detectors at one FTU to respectively detect three-phase and zero of corresponding line switches of a feeder circuit Current in the phase circuit (step 300). After receiving the current signal of the current detector by the four digit signal processing circuits, the root mean square value of each period is calculated for the current of each phase (step 305). Receiving, by a microprocessor, signals from the four sets of digital signal processing circuits, i.e., the root mean square value of each cycle of the current of each phase (step 310); the microprocessor measures the received phases The current rms value for each cycle is compared to the starting current set by the FTU 10 (step 315). If the current is in the phase of the preset number of cycles The rms value is greater than a set range of the starting current of the FTU 10 (this condition is the first requirement for generating the fault flag), and the final current value is lower than a set minimum current (relative to the normally energized current, such as 3) The ampere value of the ampere is that the corresponding line switch must have an accidental trip to generate a fault flag (step 320). Transfer the fault flag to the control center. The control center serves as the basis for judging the feeder accident section. Therefore, the control center can know that the phase at the line switch has failed (step 325). If the above conditions are not met, the microprocessor 40 checks that when the phase current values exceed the first set of values of the CO/LCO and continuously exceed a predetermined time (eg, 20 seconds or more), the microprocessor 40 will re-determine. Check if the system power meets the above requirements (step 330).

This case provides the function of detecting the fault current of the line through the FTU. The reference value is the starting current set by the electric 驿3. This value is quite stable, so this method will not be misjudged by the change of the line. According to this, the correct fault flag is generated for the control center to be used as the basis for judging the feeder accident section. Therefore, the control center can know that the segment and the phase of the fault occur at the relevant line switch. The method started in this case is quite simple, its accuracy is high, and the fault signal and control center can be provided immediately, which is not the same as the above-mentioned conventional technology.

This case is quite in line with actual needs. The specific improvement of the existing defects is obviously a breakthrough improvement advantage compared with the prior art, and it has an improvement in efficacy and is not easy to achieve. The case has not been disclosed or disclosed in domestic and foreign literature and market, and has complied with the provisions of the Patent Law.

The detailed description of the preferred embodiments of the present invention is intended to be limited to the scope of the invention, and is not intended to limit the scope of the invention. The patent scope of this case.

20‧‧‧ Current Detector

30‧‧‧Digital signal processing circuit

40‧‧‧Microprocessor

45‧‧‧Logic Processing Unit

50‧‧‧Control Center

70‧‧‧ display unit

Claims (10)

A smart feeder fault detection system is used in a feeder circuit, wherein the feeder circuit includes a power source, and the power is transmitted to the downstream load terminal via the feeder line, and the plurality of line switches are passed between; The connection point of the road is installed with electricity as a trip feeder;; the feeder information end device (that is, FTU) is arranged at each line switch; each feeder line includes a three-phase line with a phase difference of 120 degrees and one An N-phase circuit; each FTU is coupled to the control center to transmit the voltage and current conditions at the detected line switch to the control center, the system includes: four sets of current detectors are configured in an FTU for respectively Detecting a current in a three-phase and zero-phase circuit of a corresponding line switch in a feeder circuit; a plurality of digital signal processing units respectively connected to corresponding current detectors for receiving a current signal of the current detector Thereafter, the rms value of each period is calculated for the current of each phase; a microprocessor receives signals from the four sets of digital signal processing circuits, that is, each period of the current of each phase a root value; wherein the microprocessor includes a logic processing unit, the logic processing unit includes fault determination logic; the microprocessor sets the current rms value and power of each period measured by each phase received The starting current comparison, if at the first predetermined number of cycles, the current rms value of the phase is greater than a set range of the starting current set by the power, and in another second predetermined number After the cycle, the current value is lower than a set minimum current, so that if the system does not provide power to the feeder line, it indicates that there is an accident trip, thus generating a fault flag; and transmitting the fault flag to the control center for control The center serves as the basis for judging the feeder accident section; therefore, the control center can know that the section and the phase of the fault occur at the relevant line switch. For example, in the smart feeder fault detection system of claim 1, the preset number of cycles is the basic fastest trip time. For example, the smart feeder fault detection system of claim 1 of the patent scope, wherein the preset number of cycles is 3 current cycles. For example, the smart feeder fault detection system of claim 1 includes four digital signal processing units respectively connected to corresponding current detectors. For example, in the intelligent feeder fault detection system of claim 1, wherein the digital signal processing unit is constructed in the microprocessor, and the signal values measured by the four sets of current detectors are directly sent to the microprocessor. The digital signal processing unit calculates the root mean square value of each period for the current of each phase. For example, the smart feeder fault detection system of claim 1 includes a memory connected to the microprocessor, which is used to store the calculation program required by the system, and memorizes the current obtained by each phase and its period. The square root value, these values are stored in a time-corresponding manner for the control center to access for later data analysis. For example, the smart feeder fault detection system of claim 1 includes a display unit connected to the processor for displaying the processing result and the line condition of the processor. For example, the smart feeder fault detection system of claim 1 of the patent scope, wherein the fault is a fault trip, means that if the feeder is in the feed and the feeder is short-circuited, the instantaneous current will exceed the rated value, and Resulting in a first predetermined number of cycles, the current rms value of the phase is greater than a set range of the starting current set by the power, and the final current value is lower than a set minimum current, so that it can be regarded as When the system does not provide power to the feeder line, it can be determined that the line has tripped. For example, the smart feeder fault detection system of claim 1 of the patent scope, wherein the fault is an input failure means that if the feed current is zero and the feeder has a short circuit fault, the instantaneous current will exceed the rated value, and Resulting in a first predetermined number of cycles, the current mean square value of the phase is greater than a set range of the starting current set by the power, and the final current value is lower than a set minimum current, so that it can be regarded as When the system does not provide power to the feeder line, it can be determined that the line has tripped. A smart feeder fault detection method for detecting a fault in a feeder circuit, wherein the feeder circuit includes a power source, and the power is transmitted to the downstream load end via the feeder line, and the plurality of line switches are passed through; The switch is equipped with a feeder information end device (that is, FTU); each feeder line includes a three-phase line with a phase difference of 120 degrees and an N-phase circuit; each FTU is connected to the control center to detect the detected node The voltage and current conditions are transmitted to the control center, and the method includes the steps of: applying four sets of current detectors at one FTU for detecting currents in the three-phase and zero-phase circuits of a feeder circuit; After receiving the current signal of the current detector, the digital signal processing circuit calculates the root mean square value of each period for the current of each phase; and receives signals from the four groups of digital signal processing circuits by a microprocessor, that is, each phase The rms value of each cycle of the current; the microprocessor compares the rms current of each cycle measured by each phase received with the initial current set by the power; if at the first For a plurality of cycles, the current rms value of the phase is greater than a set range of the starting current set by the power, and in another second predetermined number of cycles, the final current value is lower than a set value. Very low current, so that the system does not provide power to the feeder line, then the table is certain Therefore, the fault flag is generated only when the trip occurs; the fault flag is transmitted to the control center; the control center is used as the basis for judging the feeder accident section; therefore, the control center can know that the section and the phase of the fault occur at the relevant line switch. And if the above conditions are not met, the microprocessor checks whether the phase current value exceeds the first set value of the power and continuously exceeds a predetermined time, then it will re-determine whether the check system power meets the above Essentials.