CN107045092B - Intelligent detection device and method for low-voltage alternating-current ring network for station - Google Patents
Intelligent detection device and method for low-voltage alternating-current ring network for station Download PDFInfo
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- CN107045092B CN107045092B CN201710341740.5A CN201710341740A CN107045092B CN 107045092 B CN107045092 B CN 107045092B CN 201710341740 A CN201710341740 A CN 201710341740A CN 107045092 B CN107045092 B CN 107045092B
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Abstract
The invention designs and develops an intelligent detection device and method for a station low-voltage alternating-current ring network, which monitors the voltage of two sections of alternating-current buses in real time through the device, starts a power supply alternating-current conversion unit when the bus voltage is in a reasonable range, changes the voltage phases of two groups of low-voltage alternating-current buses, and can judge that the ring network problem exists in a station low-voltage alternating-current system when a current measuring instrument finds that the station variable-current output before the phase is increased and the station variable-current output after the phase is delayed is reduced in the phase change process. After the looped network problem exists, the power supply alternating current conversion unit and the power correction unit are jointly controlled through an intelligent algorithm of the decision control unit, so that the electrical parameters of the low-voltage alternating current system buses for the two groups of stations are adjusted to be consistent to the maximum extent, the damage of the alternating current looped network is reduced, and the alarm feedback is immediately given.
Description
Technical Field
The invention relates to the technical field of substation electric equipment detection devices, in particular to a substation low-voltage alternating-current looped network intelligent detection device and method.
Background
The transformer substation low-voltage alternating-current system is a power supply source of all electric equipment of a transformer substation and is related to normal operation of motors of primary main equipment such as a circuit breaker, a disconnecting link, a main transformer fan and the like in the transformer substation. For a direct current system of a protection device, a main power supply system is obtained through low-voltage alternating current rectification conversion, and daily office power supply and construction power consumption are also provided, so that a substation transformer-substation 380V alternating current system is the most important power supply system in a transformer substation, and a substation transformer, an alternating current bus, substation protection and a spare power automatic switching device which form the low-voltage alternating current system are all key equipment which are closely concerned by transformer substation operation and maintenance workers.
However, in the project of transforming transformer substation production, the construction method has no idea of the control loop and signal wiring transformed by the previous construction project, and it is easy to cause misconnection according to experience, and further cause the parallel operation of the ac system at the load power end, and form the ac loop current of the transformer for station, resulting in extra power loss and serious consequences such as line burnout, etc., the single-phase ring network will cause the zero sequence protection action of the station under the condition of insufficient insulation, and the three-phase ring network will also cause the failure of correct operation of the backup automatic switching device due to the detection of the voltage of the bus ring network when the upper-level power supply is under voltage loss. According to the requirement of the technical specification S.00.00.05/PM.0400.0005 of an alternating current power supply system for a transformer substation of Guangdong power grid company, a single bus divided according to a working transformer is adopted as a power bus for the substation, a section or interconnection breaker can be configured between two adjacent sections of working buses, power supply and separation operation are preferably carried out simultaneously, and an automatic switching device is arranged. Therefore, under normal conditions, two groups of alternating current power supplies which are operated in a row should not have the ring network connection condition, and the alternating current ring network for the substation to change the low side endangers the normal operation of the alternating current system, so that an effective method for timely detecting and solving the problem of the alternating current ring network for the substation is urgently needed.
Disclosure of Invention
At present, the low-voltage alternating-current ring network detection method for the station is less, and the method mainly depends on manual on-site line inspection discovery and a carrier signal injection method.
The manual on-site line inspection is the most original alternating current looped network detection method, and the accidents are caused by the fact that the manual line inspection cannot be achieved frequently when the looped network on-site occurs in construction, depending on the working experience of power transformation operation and maintenance personnel and the familiarity of the power transformation operation and maintenance personnel on the site. And aiming at the construction site with complex reconstruction, the alternating current looped network has many hidden trouble points, and the power supply wiring confirmation in the acceptance stage is difficult to ensure the detection in place. Therefore, the timeliness of manual on-site line inspection for detecting the alternating current looped network problem is poor, and the method is not suitable for the current situation that the existing power grid transformation project is more.
The principle of the carrier signal injection method is that a signal transmitter is installed on a bus at one end of an alternating current system, a signal receiver is installed on a bus at the other end of the alternating current system, the transmitter is used for injecting carrier signals into the alternating current 380V bus, whether the carrier signals can be detected by the signal receiver or not is detected, and when the signals are detected successfully, the fact that a looped network loop exists in the alternating current system can be judged. The detection method is visual and simple, but in practical application, because the cable distributed capacitance is large, the carrier signal is easy to attenuate in a looped network loop. Meanwhile, the load end of the station alternating current system is generally in a TN-C-S connection mode, the electricity consumption of a single-phase load inevitably causes three phases to be inconsistent, the harmonic interference is large, and therefore a carrier signal injection method is easily interfered and misdetected, and the reliability is insufficient.
In view of the above, it is urgently needed to design a more reliable and efficient detection device and method for low-voltage ac ring network for stations.
The invention designs and develops an intelligent detection device and method for a low-voltage alternating-current ring network for a station, wherein the detection device comprises two groups of alternating-current bus voltage monitoring instruments, two groups of low-voltage side current monitoring instruments for the station, two groups of power supply alternating-current conversion units, two groups of power correction units and a decision control unit with a man-machine interaction function. The device monitors the voltage of two sections of alternating current buses in real time, when the bus voltage is in a reasonable range, the power supply alternating current conversion unit is started, the voltage phases of two groups of low-voltage alternating current buses are changed, and in the phase change process, when the current measuring instrument finds that the station variable current output before the phase is increased and the station variable current output after the phase is delayed is reduced, the looped network problem of the station variable-voltage alternating current system can be judged. After the looped network problem exists, the power supply alternating current conversion unit and the power correction unit are jointly controlled through an intelligent algorithm of the decision control unit, so that the electrical parameters of the low-voltage alternating current system buses for the two groups of stations are adjusted to be consistent to the maximum extent, the harm of the alternating current looped network is reduced, and the alarm feedback is immediately carried out.
The invention provides an intelligent detection device for a low-voltage alternating-current ring network for a station, which has the specific technical scheme that:
the utility model provides a station is with becoming low voltage alternating current looped netowrk intellectual detection system device which includes: two groups of alternating current bus voltage monitoring instruments, two groups of low-voltage side current monitoring instruments for stations, two groups of power supply alternating current conversion units, two groups of power correction units and a decision control unit;
the alternating-current bus voltage monitoring instrument is connected with the decision control unit, the two groups of instruments are respectively arranged on the two sections of alternating-current buses, the voltage amplitude and the voltage phase of the three-phase voltage of the two sections of buses of the alternating-current system are monitored in real time, and the measurement result is fed back and transmitted to the decision control unit;
the low-voltage side current monitoring instrument for the station is connected with the decision control unit, the two groups of instruments are respectively arranged between the two groups of low-voltage side switches for the station and the power supply alternating current conversion unit, output current from a low-voltage side wire outlet of the transformer for the station to an alternating current bus is monitored in real time, and a measurement result is fed back and transmitted to the decision control unit;
the power supply alternating current conversion unit is a field execution module of the alternating current looped network intelligent detection device, is connected with the decision control unit, receives a control command of the decision control unit, changes the amplitude and the phase of the output voltage of the alternating current power supply, and feeds back and transmits an action result of changing the amplitude and the phase of the output voltage of the alternating current power supply to the decision control unit;
the power correction unit is a field execution module of the intelligent detection device of the alternating current ring network, is connected with the decision control unit, receives a control command of the decision control unit, changes the three-phase unbalanced load to match with the alternating current conversion unit of the power supply, and feeds back and transmits an action result of changing the three-phase unbalanced load to the decision control unit;
the decision control unit is a central control module of the intelligent low-voltage alternating current ring network detection device, starts a ring network detection algorithm according to the change of the electric quantity detected by each instrument, controls the alternating current conversion unit and the power correction unit of the power supply, further judges the ring network according to the change of the output current of the variable-low side of the two stations, further controls the alternating current conversion unit and the power correction unit of the power supply if the ring network exists, timely reduces the current influence of the ring network, and outputs an alarm signal to remind a user of knowing the fault of the ring network.
Preferably, the two sets of power supply conversion units are respectively installed between the station low-voltage side current monitoring instrument and the low-voltage alternating-current outgoing line, and the low-voltage alternating-current outgoing line is connected with the alternating-current bus.
Preferably, the two sets of power correction units are respectively installed between the station low-voltage side current monitoring instrument and the low-voltage alternating-current outgoing line, and the low-voltage alternating-current outgoing line is connected with the alternating-current bus.
Preferably, a section switch is arranged between the two sections of alternating current buses.
Compared with the prior art, this station is with step-down alternating current looped netowrk intelligent detection device's beneficial effect is:
1. two sets of low-voltage alternating current systems are changed in a variable phase control mode, and when a looped network occurs, the problem of the alternating current looped network can be accurately judged according to the current change condition;
2. and an alternating current looped network detection mode combining abrupt change starting and power supply conversion control is adopted, so that strict online full-time monitoring is realized.
The invention also provides a detection method of the intelligent detection device for the low-voltage alternating-current ring network for the station, which has the specific technical scheme that:
a detection method of an intelligent detection device utilizing a low-voltage alternating-current ring network for a station utilizes the intelligent detection device of the low-voltage alternating-current ring network to monitor three-phase voltages of two sections of buses of an alternating-current system in real time;
the detection method comprises the following steps:
s1, starting alternating current looped network detection;
s2, sending an alternating current conversion command to the two groups of power supply alternating current conversion units through the decision control unit, and reading current data of the station low-voltage side current monitoring instrument at the appointed time;
s3, processing and comparing the current data to obtain an alternating current looped network conclusion;
and S4, after the looped network problem is detected, the control commands of the alternating current conversion unit and the power correction unit are given according to the alternating current looped network conclusion, and the adverse effect caused by the looped network is relieved.
Compared with the prior art, the detection method has the beneficial effects that:
1. the detection method can effectively detect the three-phase ring network, the single-phase ring network and the two-phase ring network, the detection effect can be accurate to which phase, and the ring network fault maintenance efficiency is improved;
2. the method provides timely automatic control processing after the looped network detection judgment is effective, corrects unbalanced power, keeps the power supply voltage consistent to the maximum extent, reduces looped network backflow, reduces harm caused by the looped network, and strives for the AC system to be stable in the optimal running state before the looped network is overhauled and started.
Drawings
Fig. 1 is a schematic diagram of the intelligent detection process of the low-voltage alternating-current ring network.
Description of reference numerals: 1- #1 station variation; 11-power supply ac conversion unit 1; 12-station low-voltage side current monitoring instrument 1; 13-ac bus 1; 14-alternating bus voltage monitoring instrument 1; 15-equivalent load 1; 16-power correction unit 1; 2- #2 station variation; 21-power ac conversion unit 2; 22-a station-use low-voltage side current monitoring instrument 2; 23-alternating current bus 2; 24-alternating current bus voltage monitoring instrument 2; 25-equivalent load 2; 26-power correction unit 2;4, a section switch; 5-decision unit.
Detailed Description
The drawings are for illustrative purposes only and are not to be construed as limiting the patent; for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationships depicted in the drawings are for illustrative purposes only and should not be construed as limiting the present patent.
As shown in fig. 1, an intelligent detection device for a low-voltage alternating-current ring network for a station includes: the system comprises two groups of alternating current bus voltage monitoring instruments (14, 24), two groups of low-voltage side current monitoring instruments (12, 22) for stations, two groups of power supply alternating current conversion units (11, 21), two groups of power correction units (16, 26) and a decision control unit (5);
alternating current bus voltage monitoring instruments (14, 24) are connected with the decision control unit (5), two groups of instruments are respectively arranged on two sections of alternating current buses (13, 23), the voltage amplitude and the voltage phase of three-phase voltage of the two sections of buses of the alternating current system are monitored in real time, and the measurement result is fed back and transmitted to the decision control unit (5);
the station low-voltage side current monitoring instruments (12 and 22) are connected with the decision control unit (5), the two groups of instruments are respectively arranged between the two groups of station low-voltage side switches and the power supply alternating current conversion units (11 and 21), output currents from the outgoing lines to the alternating current bus of the station transformer low-voltage side are monitored in real time, and measurement results are fed back and transmitted to the decision control unit (5);
the power supply alternating current conversion units (11, 21) are field execution modules of the alternating current looped network intelligent detection device, the two sets of power supply conversion units are respectively arranged between the station low-voltage side current monitoring instrument and the low-voltage alternating current outgoing line, and the low-voltage alternating current outgoing line is connected with the alternating current bus. The power supply alternating current conversion units (11, 21) are connected with the decision control unit (5), receive the control command of the decision control unit (5), change the amplitude and the phase of the output voltage of the alternating current power supply, and feed back and transmit the action result of changing the amplitude and the phase of the output voltage of the alternating current power supply to the decision control unit (5);
the power correction units (16, 26) are field execution modules of the intelligent detection device of the alternating current looped network, the two sets of power correction units are respectively arranged between the low-voltage side current monitoring instrument for the station and the low-voltage alternating current outgoing line, and the low-voltage alternating current outgoing line is connected with the alternating current bus. The power correction unit is connected with the decision control unit (5), receives a control command of the decision control unit (5), changes the three-phase unbalanced load to match with the power supply alternating current conversion unit, and feeds back and transmits an action result of changing the three-phase unbalanced load to the decision control unit;
the decision control unit (5) is a central control module of the intelligent low-voltage alternating current looped network detection device, a looped network detection algorithm is started according to the change of the electric quantity detected by each instrument, the alternating current power conversion units (11, 21) and the power correction units (16, 26) are controlled, the looped network is further judged according to the change of the output current of the variable low side of the two stations, if the looped network exists, the alternating current power conversion units (11, 21) and the power correction units (16, 26) are further controlled, the current influence of the looped network is timely reduced, and an alarm signal is output to remind a user of knowing the looped network fault.
The specific method is described as follows: and detecting and starting the alternating current looped network.
The looped network detection provides a manual control starting mode and a self-detection starting mode.
The manual control starting mode is mainly based on a human-computer interaction interface in a user operation decision control unit, when the bus voltage meets a rated range, an alternating current looped network detection algorithm program is forcibly started, and the method can be set to start looped network detection at fixed time.
The self-detection starting mode mainly changes the detection result according to the bus voltage quantity, the voltage amplitude and the phase of the two groups of alternating current buses are different under the normal condition, and the two groups of power systems are not influenced by each other. When the looped network occurs in the alternating current circuit, the bus voltage and the phase position can be suddenly changed, and when one of the amplitude value and the phase sudden change quantity reaches a preset threshold value, an alternating current looped network detection algorithm program is started.
AC looped network detection control and judgment
After the alternating current ring network detection algorithm is started, an alternating current conversion command is sent to the two groups of alternating current conversion units through the decision control unit. The method comprises two control steps:
controlling step 1: measuring low-voltage side current I for #1 station before operation 011 Measuring the low-voltage side current I for the #2 station 012 Controlling the AC conversion unit 1 to output the power supply voltage U 11 Is advanced by phi 1, controls the AC conversion unit 2 to output the power supply voltage U 12 Is delayed by phi 1, and the low-voltage side current I for the station # 1 is measured after the action is finished and delayed by 3 seconds 11 Measuring the low-voltage side current I for the #2 station 12 . And recovering the output power supply phases of the two groups of buses after the current measurement is successful.
And a control step 2: measurement of Low-Voltage-side Current I for #1 station before operation 021 Measuring the low-voltage side current I for the #2 station 022 Controlling the AC conversion unit 2 to output the power supply voltage U 22 Is controlled to output a power supply voltage U by the AC conversion unit 1 21 Is delayed by phi 1, and the low-voltage side current I for the station # 1 is measured after the action is finished and delayed by 3 seconds 21 Measuring the low-voltage side current I for the #2 station 22 . And recovering the output power supply phases of the two groups of buses after the current measurement is successful.
Will measure the current I 011 Can be divided into three phases to obtain I 011A 、I 011B 、I 01C The other currents are defined in the same way.
After all the control steps are finished, the AC looped network conclusion under different conditions can be obtained according to the following criteria.
Three-phase looped network:
when satisfying I 11A -I 011A >k*I 011A 、I 11B -I 011B > k*I 011B 、I 11C -I 011C > k*I 011C ，I 012A -I 12A > k*I 012A 、I 012B -I 12B > k*I 012B 、I 012C -I 12C > k*I 012C While simultaneously satisfying I 22A -I 022A >k*I 022A 、I 22B -I 022B > k*I 022B 、I 22C -I 022C > k*I 022C ，I 021A -I 21A > k*I 021A 、I 021B -I 21B > k*I 021 、I 021C -I 21C > k*I 021C The existence of the three-phase simultaneous ring network in the alternating current system can be uniquely judged.
Where k is a positively correlated variable with φ 1, there is k = f (φ 1).
Single-phase looped netowrk:
when satisfying I 11A -I 011A >k*I 011A ，I 012A -I 12A > k*I 012A While simultaneously satisfying I 22A -I 022A >k*I 022A ，I 021A -I 21A > k*I 021A The existence of the A-phase single-phase ring network in the alternating current system can be effectively judged.
When satisfying I 11B -I 011B >k*I 011B ，I 012B -I 12B > k*I 012B While simultaneously satisfying I 22B -I 022B >k*I 022B ，I 021B -I 21B > k*I 021B The existence of a B-phase single-phase ring network in the alternating current system can be effectively judged.
When satisfying I 11C -I 011C >k*I 011C ，I 012C -I 12C > k*I 012C While simultaneously satisfying I 22C -I 022C >k*I 022C ，I 021C -I 21C > k*I 021C The existence of the C-phase single-phase ring network in the alternating current system can be effectively judged.
Two-phase ring network:
when I is satisfied 11A -I 011A >k*I 011A 、I 11B -I 011B > k*I 011B ，I 012A -I 12A > k*I 012A 、I 012B -I 12B > k*I 012B While simultaneously satisfying I 22A -I 022A >k*I 022A 、I 22B -I 022B > k*I 022B ，I 021A -I 21A > k*I 021A 、I 021B -I 21B > k*I 021 The existence of the same time ring network of A phase and B phase in the alternating current system can be effectively judged.
When I is satisfied 11A -I 011A >k*I 011A 、I 11C -I 011C > k*I 011C ，I 012A -I 12A > k*I 012A 、I 012C -I 12C > k*I 012C While simultaneously satisfying I 22A -I 022A >k*I 022A 、I 22C -I 022C > k*I 022C ，I 021A -I 21A > k*I 021A 、I 021C -I 21C > k*I 021C The existence of the time ring network with the same A phase and C phase in the alternating current system can be effectively judged.
When I is satisfied 11B -I 011B > k*I 011B 、I 11C -I 011C > k*I 011C ，I 012B -I 12B > k*I 012B 、I 012C -I 12C > k*I 012C While simultaneously satisfying I 22B -I 022B > k*I 022B 、I 22C -I 022C > k*I 022C ，I 021B -I 21B > k*I 021 、I 021C -I 21C > k*I 021C The existence of the ring network with the same phase B and phase C in the alternating current system can be effectively judged.
And (3) out-of-phase ring network:
under the condition of an out-phase looped network, an alternating current system is equivalent to an interphase short circuit due to too large phase difference, at the moment, the loop current is too large, the triggering station is subjected to overcurrent protection, the power supply of the loop is immediately cut off by the inherent electric protection action, and therefore the condition that the looped network is detected and found out of faults by the alternating current looped network does not need to be waited.
AC looped network emergency regulation
And after the looped network problem is detected, the control commands of the alternating current conversion unit and the power correction unit are given according to the looped network judgment condition.
When a three-phase alternating-current ring network occurs, three-phase voltage amplitudes Uma1, umb1 and Umc1 and voltage phases phi a1, phi b1 and phi c1 of an alternating-current bus 1 are obtained through detection, and three-phase voltage amplitudes Uma2, umb2 and Umc2 and voltage phases phi a2, phi b2 and phi c2 of an alternating-current bus 2 are obtained through detection.
If the Uma1 is larger than the Uma2, firstly, the Uma1= Uma2 is adjusted through the power supply conversion unit, when the adjustment is unsuccessful, the two groups of power correction units are controlled, the A-phase side parallel capacitors in the power correction units 2 are put into the power correction units one by one, the reactive input of the A phase in the alternating-current bus 2 is increased, the voltages of the two groups of buses are continuously detected, and when the Uma1= Uma2 is met, the power correction strategy is ended. And when all the A-phase side parallel capacitors in the power correction unit 2 are still Uma1> Uma2, starting the A-phase side parallel reactors which are put into the power correction unit 1 one by one, continuously detecting two groups of bus voltages, and finishing the power correction strategy when Uma1= Uma2 is met.
If Umb1> Umb2, first enabling Umb1= Umb2 through power supply conversion unit adjustment, and when the adjustment is unsuccessful, controlling two groups of power correction units, putting the power correction units 2 into the B-phase side parallel capacitors one by one, increasing the reactive input of the B phase in the alternating-current bus 2, continuously detecting two groups of bus voltages, and when Umb1= Umb2 is met, ending the power correction strategy. When all the B-phase side parallel capacitors in the power correction unit 2 are put into the power correction unit, the voltage of the B-phase side parallel capacitors put into the power correction unit 1 one by one is still Umb1> Umb2, two groups of bus voltages are continuously detected, and when the voltage of Umb1= Umb2 is met, the power correction strategy is ended.
If Umc1> Umc2, firstly, umc1= Umc2 is adjusted through a power supply conversion unit, when the adjustment is unsuccessful, two groups of power correction units are controlled, C-phase side parallel capacitors in the power correction units 2 are put into the power correction units one by one, reactive input of C-phase in the alternating-current bus 2 is increased, two groups of bus voltages are detected continuously, and when the Umc1= Umc2 is met, a power correction strategy is ended. And when all the C-phase side parallel capacitors in the power correction unit 2 are put into the power correction unit, still Umc1> Umc2, starting the C-phase side parallel reactors put into the power correction unit 1 one by one, continuously detecting two groups of bus voltages, and finishing the power correction strategy when Umc1= Umc2 is met.
If φ a1> φ a2, φ a1= φ a2 through the AC/AC conversion adjustment in the power conversion unit, and the power correction strategy is ended when φ a1= φ a2 is satisfied.
If φ b1> φ b2, φ b1= φ b2 is adjusted through AC/AC conversion in the power conversion unit, and the power correction strategy is ended when φ b1= φ b2 is satisfied.
If φ c1> φ c2, φ c1= φ c2 through the AC/AC conversion adjustment in the power conversion unit, the power correction strategy is ended when φ c1= φ a2 is satisfied.
Aiming at the conditions of a single-phase ring network and a two-phase ring network, the adjustment strategy also adjusts the phase line related to the ring network, and the method is the same.
Description of intelligent detection principle of AC looped network
The two sets of alternating current power supply systems do not have the looped network problem under the normal condition, so the low-voltage power supply systems are independent systems and do not influence each other. After the looped network is formed, the two sets of power supply systems are electrically connected, so that a looped network loop is formed according to different looped network conditions, and unnecessary loop current is generated for the transformer for the station.
Due to the difference of the upper-level power supply and the station variable impedance topology, the two sets of low-voltage 380V power supply sources are independent and different in voltage amplitude and phase. If the looped network occurs, the looped network instantaneous station uses the power supply source with the low-voltage side outgoing line, the electrical quantity sudden change occurs due to the electrical connection, and the power supply source is changed from the transient state to another stable state, so that the method can be used as a starting method for the looped network self-detection.
For looped network detection, whether a loop current exists can be checked through the electrical change of a control object. According to the mathematical model of station transformer loop backflow, when the three-phase voltage phase of power supply 1 exceeds the three-phase voltage phase of power supply 2, active power will be sent from the voltage phase leading end to the voltage phase lagging end, so an effective loop backflow will be formed, and power supply 1 increases active output components on the original current output, and power supply 2 will reduce active output components on the original current output. If the looped network circuit is switched on, loop current is inevitably formed at two ends of the power supply with the phase difference, and if the looped network circuit does not exist, the two sets of alternating current systems are not interfered with each other, and the loop current does not exist. Therefore, whether the looped network exists can be effectively judged by detecting the current changes of the power supply 1 and the power supply 2. If the single-phase looped network (such as an A-phase looped network), the looped network is connected with looped network current, the change of the conducting phase current conforms to the change rule of the output current of the three-phase power supply, and the non-conducting phase (such as a B-phase looped network and a C-phase looped network) circulates normal operation current through a neutral line due to a three-phase four-wire system and is not influenced by the looped network current of the looped network.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
Claims (3)
1. The utility model provides a station is with becoming low voltage alternating current looped netowrk intellectual detection system device which includes: the system comprises two groups of alternating current bus voltage monitoring instruments (14, 24), two groups of low-voltage side current monitoring instruments (12, 22) for stations, two groups of power supply alternating current conversion units (11, 21), two groups of power correction units (16, 26) and a decision control unit (5);
alternating current bus voltage monitoring instruments (14, 24) are connected with the decision control unit (5), two groups of instruments are respectively arranged on two sections of alternating current buses (13, 23), the voltage amplitude and the voltage phase of three-phase voltage of the two sections of buses of the alternating current system are monitored in real time, and the measurement result is fed back and transmitted to the decision control unit (5);
the station low-voltage side current monitoring instruments (12 and 22) are connected with the decision control unit (5), the two groups of instruments are respectively arranged between the two groups of station low-voltage side switches and the power supply alternating current conversion units (11 and 21), output currents from the outgoing lines to the alternating current bus of the station transformer low-voltage side are monitored in real time, and measurement results are fed back and transmitted to the decision control unit (5);
the power supply alternating current conversion units (11, 21) are field execution modules of the alternating current looped network intelligent detection device, are connected with the decision control unit (5), receive a control command of the decision control unit (5), change the amplitude and the phase of the output voltage of the alternating current power supply, and feed back and transmit the action result of changing the amplitude and the phase of the output voltage of the alternating current power supply to the decision control unit (5);
the power correction units (16, 26) are field execution modules of the intelligent detection device of the alternating current ring network, are connected with the decision control unit (5), receive a control command of the decision control unit (5), change the three-phase unbalanced load to match with the alternating current conversion unit of the power supply, and feed back and transmit an action result of changing the three-phase unbalanced load to the decision control unit;
the decision control unit (5) is a central control module of the intelligent low-voltage alternating current looped network detection device, starts a looped network detection algorithm according to the change of the electric quantity detected by each instrument, controls the power supply alternating current conversion units (11, 21) and the power correction units (16, 26), judges the looped network according to the change of the output current of the low-voltage side for the two stations, further controls the power supply alternating current conversion units (11, 21) and the power correction units (16, 26) if the looped network exists, reduces the current influence of the looped network in time, and outputs an alarm signal to remind a user of knowing the looped network fault;
the two groups of power supply alternating current conversion units (11, 21) are respectively arranged between the low-voltage side current monitoring instrument for the station and the low-voltage alternating current outgoing line, and the low-voltage alternating current outgoing line is connected with alternating current buses (13, 23);
the two groups of power correction units (16, 26) are respectively arranged between the low-voltage side current monitoring instruments (12, 22) for the station and the low-voltage alternating-current outgoing line, and the low-voltage alternating-current outgoing line is connected with an alternating-current bus.
2. The intelligent detection device for the low-voltage alternating-current ring network for the station as claimed in claim 1, wherein: a section switch (4) is arranged between the two sections of alternating current buses (13, 23).
3. The detection method of the intelligent detection device for the station low-voltage alternating-current ring network according to claim 1 is used for monitoring the three-phase voltage of two sections of buses of an alternating-current system in real time by using the intelligent detection device for the low-voltage alternating-current ring network;
the detection method comprises the following steps:
s1, starting alternating current looped network detection;
s2, sending an alternating current conversion command to the two groups of power supply alternating current conversion units through the decision control unit, and reading current data of the station low-voltage side current monitoring instrument at the appointed time;
s3, processing and comparing the current data to obtain an alternating current looped network conclusion;
and S4, after the looped network problem is detected, the control commands of the alternating current conversion unit and the power correction unit are given according to the alternating current looped network conclusion, and the adverse effect caused by the looped network is relieved.
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