CN106291219B - Single-phase grounding/PT wire breakage fault automatic judging and alarming device and method - Google Patents
Single-phase grounding/PT wire breakage fault automatic judging and alarming device and method Download PDFInfo
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- CN106291219B CN106291219B CN201610883732.9A CN201610883732A CN106291219B CN 106291219 B CN106291219 B CN 106291219B CN 201610883732 A CN201610883732 A CN 201610883732A CN 106291219 B CN106291219 B CN 106291219B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/62—Testing of transformers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
Abstract
The invention discloses an automatic discrimination alarm device and method for single-phase grounding/PT disconnection faults, comprising a three-phase five-column voltage transformer, wherein the voltages of A phase, B phase and C phase of a bus/line are accessed through a primary winding, and the voltages of high phase/line are converted into low-voltage alternating voltages k1 and k2 through a secondary winding and an auxiliary winding; the unidirectional alternating-current voltage transmitter and the three-phase alternating-current voltage transmitter are both connected with the three-phase five-column voltage transformer and the programmable controller PLC at the same time, and low-voltage alternating-current voltages k1 and k2 are respectively transmitted to the unidirectional alternating-current voltage transmitter and the three-phase alternating-current voltage transmitter and are converted into direct-current voltage/direct-current signals and then transmitted to the programmable controller PLC, so that signal acquisition of zero-sequence voltages Uo, voltage amplitudes Ua, ub and Uc is realized. The device and the method provided by the invention have the advantages that the single-phase grounding/PT disconnection fault is accurately judged, the precision is high, the wiring is simple, the installation and the maintenance are easy, the hardware cost is low, and the situations of misjudgment and missed judgment are avoided.
Description
Technical Field
The invention relates to the field of electric power, in particular to an automatic discrimination alarm device and method for single-phase grounding/PT disconnection faults.
Background
PT is a voltage transformer, also called TV, and is a special transformer for measuring high voltage of a power grid, which can convert the high voltage into lower voltage according to a specified proportion, and then is connected to devices such as instruments and meters for collection or measurement, and when the voltage of the high voltage side (also called primary side or primary side) of the voltage transformer is rated voltage, the voltage of the low voltage side (also called secondary side or secondary side) is generally 100V. PT broken wire is that the high-voltage side or the low-voltage side of the voltage transformer is fused, or the loop joint of the voltage transformer is loose, broken wire, poor contact and the like, so that voltage signals can not be correctly collected, and the voltage signals are divided into the high-voltage side PT broken wire and the low-voltage side PT broken wire. Wherein, each side PT broken wire is divided into PT single-phase, two-phase and three-phase broken wires because the broken wire occurs in one phase, two-phase or three-phase. In a three-phase power system, a single phase earth connection is subject to dielectric breakdown/breakdown between only one phase conductor and earth, resulting in a short circuit to earth. Single-phase to ground shorts are the most common short-circuit faults, accounting for about 70% of the short-circuit faults. Single-phase earth faults are the most common faults of power generation and distribution systems, and occur in wet and rainy weather.
In a power system with a neutral point not grounded, single-phase earth faults and PT (potential transformer) fault faults occur, misjudgment and missed judgment are easy to occur, and if the nature and the phase of the faults cannot be timely found and accurately judged, the faults cannot be rapidly processed, so that the accident processing time is prolonged, even the accidents are enlarged, certain economic loss is caused, and the safe and stable operation of a power grid is not facilitated.
At present, a device for judging and alarming aiming at single-phase grounding/PT disconnection faults is not arranged in the power system, and if the bus/line is not provided with a complete set of protection devices, the judgment can be carried out only by relying on the experience of operators, so that the judgment is not timely, misjudgment or missed judgment is caused; even if a complete set of protection devices are arranged on some buses/lines, only PT broken line locking signals are generally sent, whether PT broken lines occur on a high-voltage side or a low-voltage side cannot be clearly distinguished, and particularly, whether the PT broken lines occur in one phase, two phases or three phases can be clearly distinguished, so that the accident handling time is prolonged; some complete sets of protection devices have simple self criteria, and sometimes send out two kinds of fault alarm information of single-phase grounding and PT disconnection at the same time, so that operators cannot directly judge the fault, the fault/accident handling is not timely, and the safe and stable operation of a power grid is influenced.
Disclosure of Invention
The invention overcomes the defects of the prior art, provides the single-phase grounding/PT wire breakage fault automatic judging and alarming device and the method, has the advantages of accurate judgment, high precision, simple wiring, easy installation and maintenance and lower hardware cost, and avoids the situations of misjudgment and missed judgment.
The invention solves the problems by adopting the following technical scheme: the single-phase grounding/PT disconnection fault automatic distinguishing and alarming device comprises
The three-phase five-column voltage transformer is connected with A-phase, B-phase and C-phase voltages of a bus/line through a primary winding, converts high-phase/line voltage into low-voltage alternating-current voltage k1 with rated voltage of 100V through a secondary winding, and converts high-phase/line voltage into low-voltage alternating-current voltage k2 with rated voltage through the secondary winding;
the unidirectional alternating-current voltage transmitter is simultaneously connected with the three-phase five-column voltage transformer and the programmable controller PLC, low-voltage alternating-current voltage k2 on an auxiliary winding of the three-phase five-column voltage transformer is transmitted to the unidirectional alternating-current voltage transmitter, the unidirectional alternating-current voltage transmitter converts the low-voltage alternating-current voltage into direct-current voltage/direct-current signals and then transmits the direct-current voltage/direct-current signals to the programmable controller PLC, and signal acquisition of zero-sequence voltage Uo on a bus/line is realized;
the three-phase alternating-current voltage transmitter is simultaneously connected with the three-phase five-column voltage transformer and the programmable controller PLC, low-voltage alternating-current voltage k1 on the secondary winding of the three-phase five-column voltage transformer is transmitted to the three-phase alternating-current voltage transmitter, the three-phase alternating-current voltage transmitter converts the low-voltage alternating-current voltage into direct-current voltage/direct-current signals and then transmits the direct-current voltage/direct-current signals to the programmable controller PLC, and signal acquisition of A-phase voltage amplitude Ua, B-phase voltage amplitude Ub and C-phase voltage amplitude Uc on a bus/line is realized;
and the programmable controller PLC is connected with the touch screen and used for comparing and analyzing to obtain fault type/phase information, sending out an alarm signal and displaying the alarm signal on the touch screen.
The device is suitable for a power system with non-grounded neutral points, particularly suitable for single-phase grounding and PT disconnection fault discrimination of a system with non-grounded neutral points of 6kV and 10kV, and adopts the voltage amplitude, voltage difference and zero sequence voltage of three-phase voltage which are not used in the prior art to comprehensively discriminate single-phase grounding/PT disconnection, and is specially used for discriminating and alarming single-phase grounding and PT disconnection faults which frequently occur and are easy to be misjudged in the power system, so that the type and the phase of the fault can be accurately discriminated, and the fault type is single-phase grounding or PT disconnection.
For single-phase earth faults, the device can accurately judge whether the fault phase is A phase, B phase or C phase; for PT disconnection fault, this device can accurately judge what side the fault takes place in: whether high or low pressure side; and judging which phase is A, B, C and which two phases are three phases of the phase where the fault occurs, so that the fault treatment is more targeted, and the fault treatment time is shortened. The scheme can judge the fault type and the fault phase, is not used in the prior art, and belongs to the initiative. The device directly collects the phase voltages of each phase, directly reflects the state of each phase, and has more direct criterion compared with the prior art that line voltages are collected first and then converted into phase voltages; the PT three-phase disconnection is judged by calculating the voltage difference value without collecting the phase current, so that the collection device is few, the wiring is simple, and the hardware cost is low.
In order to better realize monitoring the fault process, the data of the duration time and the intermittent grounding/disconnection times of the single-phase grounding/PT disconnection are provided, a basis is provided for fault analysis and processing or state maintenance, and the programmable controller PLC is internally provided with a timer and a counter, so that the measurement of the duration time and the intermittent times of the single-phase grounding or PT disconnection can be realized and displayed through a touch screen.
The automatic discrimination and alarm method for single-phase grounding/PT disconnection faults adopts an automatic discrimination and alarm device as any one of claims 1 or 2, and comprises the following steps:
step A) automatically judging and initializing an alarm device, continuously collecting three-phase voltage amplitudes Ua, ub, uc and zero sequence voltages Uo of a bus/line in a neutral point ungrounded power system, judging whether the system to be tested is in an operating state according to whether the collected three-phase voltage amplitudes Ua, ub, uc and zero sequence voltages Uo are zero or not and the states of a related breaker and an isolation disconnecting link, returning if the system is in an off-stream state, and calculating differences DeltaUa, deltaUb and DeltaUc of the three-phase voltage amplitudes if the system is in the operating state, wherein the differences are differences between measurement values of two scanning periods;
step B), comprehensively judging whether a fault occurs or not by a Programmable Logic Controller (PLC) according to the amplitude value, the voltage difference value and the zero sequence voltage of the three phases, and if the fault occurs, further judging the nature and the phase of the fault are single-phase grounding, PT single-phase high-voltage side disconnection, PT single-phase low-voltage side disconnection, PT two-phase high-voltage side disconnection or PT high-low voltage side three-phase disconnection, and specifically to which phase or which two phases;
and C) performing fault alarm according to the judging result of the PLC, and displaying the fault alarm on a touch screen in the form of an optical character plate.
Further preferably, the touch screen in step C) may also display the number and duration of the fault interruption according to the timing and counting functions of the timer and counter built-in the programmable controller PLC.
Preferably, the judging method of the single-phase earth fault in the step B) is that when the collected zero sequence voltage Uo is more than 50V or the A-phase voltage difference delta Ua is more than 0.2Ue, the B-phase voltage amplitude Ub and the C-phase voltage amplitude Uc are both more than 1.2 times of rated voltage Ue, and the A-phase voltage amplitude is less than 0.8 times of rated voltage Ue, the single-phase earth fault is judged to occur in the A-phase.
Preferably, in the judging method of the PT single-phase high-voltage side broken line fault in the step B), when the collected zero sequence voltage Uo is greater than or equal to 5V or the a-phase voltage difference deltaua >0.2ue, the a-phase voltage amplitude Ua <0.8Ue, and the B, C two-phase voltage amplitudes are respectively between 0.8 and 1.0Ue, the PT high-voltage side a-phase broken line is judged.
Preferably, in the judging method of the PT single-phase low-voltage side broken line fault in the step B), when the collected zero sequence voltage Uo is less than or equal to 5V or the a-phase voltage difference value Δua >0.2ue, the a-phase voltage amplitude Ua <0.1ue, the B-phase voltage amplitude and the C-phase voltage amplitude are respectively between 0.9 and 1.05ue, and Uo is less than or equal to 5V, the PT low-voltage side a-phase broken line is judged.
Preferably, in the judging method of the PT two-phase low-voltage side broken line fault in the step B), when the collected A, B two-phase voltage difference values Δua and Δub are both greater than 0.2Ue, the voltage amplitudes of the a and B two-phase voltage are both less than 0.1Ue, and the voltage amplitude of the C phase is between 0.9 and 1.05Ue, it is determined that the PT low-voltage side A, B is broken.
Preferably, in the step B), the judging method of the PT two-phase high-voltage side disconnection or PT high-low-voltage side three-phase disconnection fault is that when the collected A, B, C three-phase voltage differences Δua, Δub and Δuc are all greater than 0.2Ue, and the amplitudes of the a and B, C three-phase voltages are all less than 0.1Ue, it is judged that the PT high-voltage side two-phase or PT high-low-voltage side three-phase disconnection is performed.
A large number of practical tests show that the method for measuring the material has the following performance advantages: the judgment is accurate, and misjudgment and missed judgment are not easy to occur; the equipment has high response speed and high accuracy; the wiring is simple, the installation and maintenance are convenient, and the portability is strong; the system has strong expandability and can be developed for the second time.
In summary, the beneficial effects of the invention are as follows:
1. the method is suitable for the single-phase grounding and PT disconnection fault discrimination of the neutral point ungrounded power system of 6kV and 10kV, and adopts three-phase voltage amplitude, voltage difference and zero sequence voltage which are not used in the prior art to comprehensively discriminate single-phase grounding/PT disconnection, and is specially used for discriminating and alarming single-phase grounding and PT disconnection faults which frequently occur and are easy to be misjudged in the power system, and the type and the phase of the fault can be accurately discriminated, and the fault type is single-phase grounding or PT disconnection.
2. The scheme directly collects the phase voltages of each phase, directly reflects the states of each phase, and has more direct criterion compared with the prior art that line voltages are collected first and then converted into phase voltages; the PT three-phase disconnection is judged by calculating the voltage difference value without collecting the phase current, so that the collection device is few, the wiring is simple, and the hardware cost is low.
3. The fault process is monitored, the duration time of single-phase grounding/PT wire breakage and the times of intermittent grounding/wire breakage are provided, and a basis is provided for fault analysis and treatment or state maintenance.
Drawings
FIG. 1 is a functional block diagram of the present invention;
fig. 2 is a flow chart of an implementation of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples and drawings, but embodiments of the present invention are not limited thereto.
Symbol description: A. b, C phase voltage amplitudes are respectively represented by symbols Ua, ub and Uc; A. the difference between the front scanning period and the rear scanning period of the B, C phase voltage amplitude is respectively represented by delta Ua, delta Ub and delta Uc; the zero sequence voltage is represented by U0; the nominal voltage is indicated by Ue. The difference value calculating method is to collect and calculate the difference between the front scanning period and the rear scanning period of the phase voltage amplitude.
Example 1:
as shown in FIGS. 1-2, the invention comprises a single-phase grounding/PT disconnection fault automatic judging and alarming device, which comprises
The three-phase five-column voltage transformer is connected with A-phase, B-phase and C-phase voltages of a bus/line through a primary winding, converts high-phase/line voltage into low-voltage alternating-current voltage k1 with rated voltage of 100V through a secondary winding, and converts high-phase/line voltage into low-voltage alternating-current voltage k2 with rated voltage through the secondary winding; the three-phase five-column voltage transformer can be replaced by three single-phase voltage transformers or one three-phase voltage transformer. In fig. 1, xD and aD are two end points of auxiliary winding access, and a, b and c are three end points of auxiliary winding access.
The unidirectional alternating-current voltage transmitter is simultaneously connected with the three-phase five-column voltage transformer and the programmable controller PLC, low-voltage alternating-current voltage k2 on an auxiliary winding of the three-phase five-column voltage transformer is transmitted to the unidirectional alternating-current voltage transmitter, and the unidirectional alternating-current voltage transmitter converts the low-voltage alternating-current voltage into a direct-current voltage/direct-current signal of 0-10V/4-20 mA and then transmits the direct-current voltage/direct-current signal to the programmable controller PLC to realize signal acquisition of zero-sequence voltage Uo on a bus/line; the zero sequence voltage Uo acquisition method can also be realized by acquiring three-phase alternating voltage through an alternating voltage acquisition device and then sending the three-phase alternating voltage into a computer (a singlechip, a single board computer and an industrial personal computer) for calculation through a program.
The three-phase alternating-current voltage transmitter is connected with the three-phase five-column voltage transformer and the programmable controller PLC at the same time, low-voltage alternating-current voltage k1 on the secondary winding of the three-phase five-column voltage transformer is transmitted to the three-phase alternating-current voltage transmitter, the three-phase alternating-current voltage transmitter converts the low-voltage alternating-current voltage into direct-current voltage/direct-current signals of 0-10V/4-20 mA and then transmits the direct-current voltage/direct-current signals to the programmable controller PLC, and signal acquisition of A-phase voltage amplitude Ua, B-phase voltage amplitude Ub and C-phase voltage amplitude Uc on a bus/line is realized;
and the programmable controller PLC is connected with a type MT6070IH5 Weilon touch screen and is used for comparing and analyzing to obtain fault type/phase information, sending an alarm signal and displaying the alarm signal on the touch screen. The programmable controller PLC can be used for comparing and analyzing to obtain single-phase grounding information, PT disconnection information, duration time, disconnection times or intermittent grounding information, and comprises an analog input module with the model of AMI0410 and a CPU module with the model of Schneider M340PLC, CPS2000, wherein the analog input module is used for converting analog input signals into digital signals and then sending the digital signals to the CPU module to realize signal acquisition of phase voltages Ua, ub, uc and zero sequence voltage Uo of buses/lines, obtaining information such as fault types/phases after comparing and analyzing, sending alarm signals and displaying the alarm signals on a touch screen for subsequent fault processing. The analog input module can be replaced by an analog-to-digital (A/D) conversion device or an alternating current sampling device; the programmable controller PLC can be replaced by a singlechip, a single-board computer, an industrial personal computer and the like; the touch screen can be replaced by other digital display devices, an upper computer or a voice alarm device;
when a single-phase grounding fault occurs in a neutral point of the power system, particularly a 6kV and 10kV system, the current is smaller in the single-phase grounding fault, a short circuit loop is not formed, the power system can continue to operate for 1-2 hours after the grounding fault is regulated by a safety operation rule of the power system, but the non-fault phase grounding voltage of the whole system is increased, and if the non-fault phase grounding fault is not handled in time, the non-fault phase insulation breakdown is possibly developed into an inter-phase short circuit, so that the fault is enlarged. PT disconnection faults can be generally divided into PT primary side disconnection and PT secondary side disconnection, and no matter which side disconnection is, the voltage of the PT secondary circuit will be abnormal. The two faults have great significance on safe and stable operation of the power system and the power grid, and the judging and alarming device comprises a set of automatic judging and alarming devices of single-phase grounding, PT primary side disconnection and secondary side disconnection, can timely and accurately judge the common single-phase grounding and PT disconnection faults of the power system bus and the line in operation, can accurately judge the specific phases of faults, solves the actual problems of the power system, avoids time extension or accident expansion caused by untimely accident treatment, and avoids immeasurable economic losses.
At present, for the system single-phase grounding/PT disconnection faults which are easy to occur and misjudge, no special single-phase grounding/PT disconnection identification and alarm device exists, and the single-phase grounding/PT disconnection identification and alarm device generally only exists in certain complete sets of protection devices as PT disconnection locking conditions. The fault process of single-phase grounding/PT disconnection is not monitored, and only one alarm message is provided, so that the analysis and the processing of subsequent faults are not facilitated. The PT disconnection judgment basis commonly used at present is generally divided into two kinds: (1) The PT symmetrical disconnection, namely the criterion of three-phase all disconnection, adopts the rated current that the three-phase voltage is less than 8V and the current of any phase is more than 0.06 times; the judging method has the following problems that the phase/line voltage and the phase current need to be acquired, the acquisition amount is large, and the hardware cost is high. In addition, the two-phase broken line at the high voltage side also meets the criterion, and misjudgment is easy to occur. (2) PT asymmetric disconnection criteria are commonly found in the following: criterion one: the negative sequence voltage is greater than 8V; and (2) a second criterion: the vector sum of the three phase voltages is greater than 18V and the difference between the modulus of at least one line voltage is greater than 20V; and (3) a criterion III: there is a difference between the modulus values of the line voltages greater than 18V. The three criteria are adopted, and the following problems exist: the three criteria are judged by only using one value of single negative sequence voltage or phase voltage, and the criteria are insufficient, so that misjudgment and missed judgment are easy to occur; the above criteria do not determine whether the PT high voltage side or low voltage side is broken, and not exactly which phase or two phases are broken; the above criteria do not monitor the disconnection process, which is not beneficial to further detection and processing of faults.
The device is suitable for a power system with a neutral point not grounded, and is particularly suitable for distinguishing single-phase grounding faults and PT disconnection faults of the neutral point not grounded systems of 6kV and 10 kV; the device adopts the voltage amplitude, the voltage difference and the zero sequence voltage of the three-phase voltage which are not used in the prior art to comprehensively judge the single-phase grounding/PT disconnection, is specially used for judging and alarming single-phase grounding and PT disconnection faults which occur frequently and are easy to judge by mistake in a power system, can accurately judge the type and the phase of the fault by verification, and is characterized in that the single-phase grounding or PT disconnection is adopted as the type of the fault.
For single-phase earth faults, the device can accurately judge whether the fault phase is A phase, B phase or C phase; for PT disconnection fault, this device can accurately judge what side the fault takes place in: whether high or low pressure side; distinguishing the phase of the fault occurrence: which phase is A, B, C and which two phases are three phases, so that fault treatment is more targeted, and fault treatment time is shortened. The scheme can judge the fault type and the fault phase, is not used in the prior art, and belongs to the initiative. The device directly collects the phase voltages of each phase, directly reflects the state of each phase, and has more direct criterion compared with the prior art that line voltages are collected first and then converted into phase voltages; the PT three-phase disconnection is judged by calculating the voltage difference value without collecting the phase current, so that the collection device is few, the wiring is simple, and the hardware cost is low.
Example 2:
this embodiment is preferably as follows on the basis of embodiment 1: the programmable controller PLC is internally provided with a timer and a counter, so that the duration time and the intermittent times of single-phase grounding or PT disconnection can be measured and displayed through a touch screen. The fault process is monitored, the duration time of single-phase grounding/PT wire breakage and the times of intermittent grounding/wire breakage are provided, and a basis is provided for fault analysis and treatment or state maintenance. The times of single-phase grounding or PT wire breakage are recorded, the duration sets of single-phase grounding or PT wire breakage are collected, summarized and output, and the method is not used in the prior art and belongs to the initiative.
Example 3:
the invention comprises a single-phase grounding/PT disconnection fault automatic judging and alarming method, which adopts an automatic judging and alarming device and comprises the following steps:
step A) automatically judging and initializing an alarm device, continuously collecting three-phase voltage amplitudes Ua, ub, uc and zero sequence voltages Uo of a bus/line in a neutral point ungrounded power system, judging whether the system to be tested is in an operating state according to whether the collected three-phase voltage amplitudes Ua, ub, uc and zero sequence voltages Uo are zero or not and the states of a related breaker and an isolation disconnecting link, returning if the system is in an off-stream state, and calculating differences DeltaUa, deltaUb and DeltaUc of the three-phase voltage amplitudes if the system is in the operating state, wherein the differences are differences between measurement values of two scanning periods;
step B), comprehensively judging whether a fault occurs or not by a Programmable Logic Controller (PLC) according to the amplitude value, the voltage difference value and the zero sequence voltage of the three phases, and if the fault occurs, further judging the nature and the phase of the fault are single-phase grounding, PT single-phase high-voltage side disconnection, PT single-phase low-voltage side disconnection, PT two-phase high-voltage side disconnection or PT high-low voltage side three-phase disconnection, and specifically to which phase or which two phases;
and C) performing fault alarm according to the judging result of the PLC, and displaying the fault alarm on a touch screen in the form of an optical character plate.
The touch screen in the step C) can display the fault intermittent times and duration according to the timing and counting functions of a timer and a counter which are arranged in the programmable controller PLC.
The judging method of the single-phase earth fault in the step B) is that when the collected zero sequence voltage Uo is more than 50V or the A-phase voltage difference delta Ua is more than 0.2Ue, the B-phase voltage amplitude Ub and the C-phase voltage amplitude Uc are both more than 1.2 times of rated voltage Ue (Ub is more than 1.2Ue and Uc is more than 1.2 Ue), and the A-phase voltage amplitude is less than 0.8 times of rated voltage Ue (Ua <0.8 Ue), the single-phase earth fault is judged to occur in the A-phase. The other B, C phase single-phase grounding judgment method is similar to the judgment, and only needs to change the phase A into the phase B or the phase C, and then other values are changed into the other two.
The judging method of the PT single-phase high-voltage side broken line fault in the step B) is that when the acquired zero sequence voltage Uo is more than or equal to 5V or the A phase voltage difference delta Ua is more than 0.2Ue, the A phase voltage amplitude Ua is less than 0.9Ue, and B, C two-phase voltage amplitudes are respectively between 0.8 and 1.0Ue (namely, ub is more than or equal to 0.8 and less than or equal to 1.0Ue, uc is more than or equal to 0.8 and less than or equal to 1.0 Ue), the PT high-voltage side A phase broken line is judged, and Ue represents rated voltage. The other B, C phase single-phase grounding judgment method is similar to the judgment, and only needs to change the phase A into the phase B or the phase C, and then other values are changed into the other two.
The judging method of the PT single-phase low-voltage side broken line fault in the step B) is that when the collected zero sequence voltage Uo is less than or equal to 5V or the A phase voltage difference delta Ua is more than 0.2Ue, the A phase voltage amplitude Ua is less than 0.1Ue, the B and C phase voltage amplitudes are respectively between 0.9 and 1.05Ue (namely, the Ub is more than or equal to 0.9 and less than or equal to 1.05Ue, the Ue is more than or equal to 0.9 and less than or equal to 1.05 Ue), and the Uo is less than or equal to 5V, the PT low-voltage side A phase broken line is judged. The other B, C phase single-phase grounding judgment method is similar to the judgment, and only needs to change the phase A into the phase B or the phase C, and then other values are changed into the other two.
The judging method of the PT two-phase low-voltage side broken line fault in the step B) is that when the collected A, B two-phase voltage difference delta Ua and delta Ub are both larger than 0.2Ue (namely delta Ua >0.2Ue and delta Ub >0.2 Ue), A, B-phase voltage amplitude is smaller than 0.1Ue, and C-phase voltage amplitude is between 0.9 and 1.05Ue (0.9 Ue is smaller than or equal to Uc and smaller than or equal to 1.05 Ue), the PT low-voltage side A, B two-phase broken line is judged. The other B, C phase single-phase grounding judgment method is similar to the judgment, and only needs to change the phase A into the phase B or the phase C, and then other values are changed into the other two.
In the step B), when the collected A, B, C three-phase voltage differences Δua, Δub and Δuc are all greater than 0.2Ue (i.e., Δua >0.2Ue, Δub >0.2Ue, Δuc >0.2 Ue), and A, B, C three-phase voltage amplitudes are all less than 0.1Ue (i.e., ua <0.1Ue, ub <0.1Ue, uc <0.1 Ue), it is determined that the PT high-voltage side two-phase or PT high-voltage and low-voltage side three-phase breaks. The other B, C phase single-phase grounding judgment method is similar to the judgment, and only needs to change the phase A into the phase B or the phase C, and then other values are changed into the other two.
A large number of practical tests show that the method for measuring the material has the following performance advantages: the judgment is accurate, and misjudgment and missed judgment are not easy to occur; the equipment has high response speed and high accuracy; the wiring is simple, the installation and maintenance are convenient, and the portability is strong; the system has strong expandability and can be developed for the second time.
The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any simple modification, equivalent variation, etc. of the above embodiment according to the technical matter of the present invention fall within the scope of the present invention.
Claims (4)
1. The single-phase grounding/PT disconnection fault automatic distinguishing and alarming device is characterized by comprising
The three-phase five-column voltage transformer is connected with A-phase, B-phase and C-phase voltages of a bus/line through a primary winding, converts high-phase/line voltage into low-voltage alternating-current voltage k1 with rated voltage of 100V through a secondary winding, and converts high-phase/line voltage into low-voltage alternating-current voltage k2 with rated voltage through the secondary winding;
the unidirectional alternating-current voltage transmitter is simultaneously connected with the three-phase five-column voltage transformer and the programmable controller PLC, low-voltage alternating-current voltage k2 on an auxiliary winding of the three-phase five-column voltage transformer is transmitted to the unidirectional alternating-current voltage transmitter, the unidirectional alternating-current voltage transmitter converts the low-voltage alternating-current voltage into direct-current voltage/direct-current signals and then transmits the direct-current voltage/direct-current signals to the programmable controller PLC, and signal acquisition of zero-sequence voltage Uo on a bus/line is realized;
the three-phase alternating-current voltage transmitter is simultaneously connected with the three-phase five-column voltage transformer and the programmable controller PLC, low-voltage alternating-current voltage k1 on the secondary winding of the three-phase five-column voltage transformer is transmitted to the three-phase alternating-current voltage transmitter, the three-phase alternating-current voltage transmitter converts the low-voltage alternating-current voltage into direct-current voltage/direct-current signals and then transmits the direct-current voltage/direct-current signals to the programmable controller PLC, and signal acquisition of A-phase voltage amplitude Ua, B-phase voltage amplitude Ub and C-phase voltage amplitude Uc on a bus/line is realized;
the programmable controller PLC is connected with the touch screen and is used for comparing and analyzing to obtain fault type/phase information, sending out an alarm signal and displaying the alarm signal on the touch screen;
the alarm method for automatically judging the alarm device comprises the following steps:
step A) automatically judging and initializing an alarm device, continuously collecting three-phase voltage amplitudes Ua, ub, uc and zero sequence voltages Uo of a bus/line in a neutral point ungrounded power system, judging whether the system to be tested is in an operating state according to whether the collected three-phase voltage amplitudes Ua, ub, uc and zero sequence voltages Uo are zero or not and the states of a related breaker and an isolation disconnecting link, returning if the system is in an off-stream state, and calculating differences DeltaUa, deltaUb and DeltaUc of the three-phase voltage amplitudes if the system is in the operating state, wherein the differences are differences between measurement values of two scanning periods;
step B), comprehensively judging whether a fault occurs or not by a Programmable Logic Controller (PLC) according to the amplitude value, the voltage difference value and the zero sequence voltage of the three phases, and if the fault occurs, further judging the nature and the phase of the fault are single-phase grounding, PT single-phase high-voltage side disconnection, PT single-phase low-voltage side disconnection, PT two-phase high-voltage side disconnection or PT high-low voltage side three-phase disconnection, and specifically to which phase or which two phases;
step C), performing fault alarm according to the judging result of the PLC, and displaying the fault alarm on a touch screen in the form of an optical character plate;
the judging method of the single-phase earth fault in the step B) is that when the collected zero sequence voltage Uo is more than 50V or the A-phase voltage difference delta Ua is more than 0.2Ue, the B-phase voltage amplitude Ub and the C-phase voltage amplitude Uc are both more than 1.2 times of rated voltage Ue, and the A-phase voltage amplitude is less than 0.8 times of rated voltage Ue, the single-phase earth fault is judged to occur in the A-phase;
the judging method of the PT single-phase high-voltage side broken line fault in the step B) is that when the acquired zero sequence voltage Uo is more than or equal to 5V or the A-phase voltage difference delta Ua is more than 0.2Ue, the A-phase voltage amplitude Ua is less than 0.8Ue, and B, C two-phase voltage amplitudes are respectively between 0.8 and 1.0Ue, the PT high-voltage side A-phase broken line is judged;
the judging method of the PT single-phase low-voltage side broken line fault in the step B) is that when the acquired zero sequence voltage Uo is less than or equal to 5V or the A phase voltage difference delta Ua is more than 0.2Ue, the A phase voltage amplitude Ua is less than 0.1Ue, the B and C phase voltage amplitudes are respectively between 0.9 and 1.05Ue, and the Uo is less than or equal to 5V, the PT low-voltage side A phase broken line is judged;
the judging method of the PT two-phase low-voltage side broken line fault in the step B) is that when the collected A, B two-phase voltage difference delta Ua and delta Ub are both larger than 0.2Ue, the amplitude of the A and B two-phase voltage is smaller than 0.1Ue, and the amplitude of the C phase voltage is between 0.9 and 1.05Ue, the PT low-voltage side A, B two-phase broken line is judged.
2. The automatic discrimination and alarm device for single-phase grounding/PT disconnection fault according to claim 1, wherein the programmable controller PLC has a timer and a counter inside, and can measure the duration and the number of disconnection times of single-phase grounding or PT disconnection and display them through a touch screen.
3. The automatic judging and alarming device for single-phase grounding/PT disconnection faults according to claim 1, wherein in the step B), the judging method of the PT two-phase high-voltage side disconnection or the PT high-low-voltage side three-phase disconnection faults is that when the acquired A, B, C three-phase voltage difference delta Ua, delta Ub and delta Uc are all larger than 0.2Ue and the amplitude of the A and B, C three-phase voltages is smaller than 0.1Ue, the PT high-voltage side two-phase or the PT high-voltage and low-voltage side three-phase disconnection is judged.
4. The automatic discrimination alarm device for single-phase earth/PT disconnection fault according to claim 1, wherein the touch screen in step C) can display the number and duration of the disconnection time of the fault according to the timing and counting function of a timer and a counter built in the programmable controller PLC.
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Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107947204A (en) * | 2017-11-09 | 2018-04-20 | 国网山东省电力公司枣庄供电公司 | Three-phase load autobalance single-phase electric energy metering device and its control method |
| CN108957243A (en) * | 2018-08-28 | 2018-12-07 | 云南电网有限责任公司电力科学研究院 | A kind of method for locating single-phase ground fault and system applied to power distribution network |
| CN109283437A (en) * | 2018-11-06 | 2019-01-29 | 国网四川省电力公司技能培训中心 | PT broken string and singlephase earth fault simulator and method |
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| CN113629671B (en) * | 2021-08-02 | 2022-09-30 | 国网江苏省电力有限公司镇江供电分公司 | 110kV line disconnection protection method for measuring low-voltage lateral line voltage of transformer |
| CN116482581B (en) * | 2023-06-20 | 2023-11-14 | 广东电网有限责任公司佛山供电局 | Transformer substation voltage transformer opening triangle voltage secondary circuit tester |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101581751A (en) * | 2009-06-11 | 2009-11-18 | 牛晓丽 | Locating method of voltage transformer disconnection |
| CN105356441A (en) * | 2015-11-17 | 2016-02-24 | 国网冀北电力有限公司张家口供电公司 | Intelligent PT harmonic elimination and phase selection method and device |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0619405B2 (en) * | 1988-08-04 | 1994-03-16 | 東京電力株式会社 | Disconnection detection device for PT secondary circuit |
| JP2004053554A (en) * | 2002-07-24 | 2004-02-19 | Hitachi Ltd | Distribution line disconnection detection system |
| CN100492034C (en) * | 2007-10-11 | 2009-05-27 | 武汉大学 | Live line measurement method and apparatus for zero phase-sequence impedance parameter of mutual inductance circuit containing T type connection wire |
| CN101651329B (en) * | 2008-12-03 | 2011-04-20 | 南京南瑞继保电气有限公司 | Judgment method of line breakage of special TV for inter-turn protection of generator |
| CN101452041B (en) * | 2008-12-26 | 2010-10-20 | 湖北省电力试验研究院 | Electrical power distribution network single-phase earth fault type and phase distinguishing method |
| CN101788633B (en) * | 2010-03-10 | 2013-02-27 | 南京南瑞继保电气有限公司 | Method for judging breakage of voltage transformer circuit |
| CN102879711A (en) * | 2012-09-29 | 2013-01-16 | 江苏省电力公司徐州供电公司 | Method for quickly positioning and monitoring faults of power distribution network |
| CN104836330B (en) * | 2015-04-16 | 2017-11-07 | 广东电网有限责任公司揭阳供电局 | Backup auto-activating device bus PT three-phases broken string quick determination method and faulty action preventing method |
| CN206132897U (en) * | 2016-10-10 | 2017-04-26 | 国网四川省电力公司技能培训中心 | Alarm device is differentiated automatically to single -phase ground connection PT disconnection fault |
-
2016
- 2016-10-10 CN CN201610883732.9A patent/CN106291219B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101581751A (en) * | 2009-06-11 | 2009-11-18 | 牛晓丽 | Locating method of voltage transformer disconnection |
| CN105356441A (en) * | 2015-11-17 | 2016-02-24 | 国网冀北电力有限公司张家口供电公司 | Intelligent PT harmonic elimination and phase selection method and device |
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