• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Method for the detection of the open phase in a three-phase electrical system, detects the open phase from the values measured by the measuring equipment or the current resulting from the current transformers connected in each phase. If the current value of a phase is equal to zero, and the value of the other two phases are equal. Or if the waveform of a phase is drawn horizontally and of zero amplitude, and the waves of the other two phases are drawn alternating, opposite, of equal amplitude and phase shift 180º. Or in phasor mode, it turns out that the open phase is a zero vector, and the non-open phases are opposite vectors of the same module. It will be concluded that we are in an open phase event and this is because the non-open phases form a closed circuit.
    公开号:ES2675010A1
    申请号:ES201700011
    申请日:2017-01-03
    公开日:2018-07-05
    发明作者:Jaime Rodrigo ZORRILLA MORALES
    申请人:Jaime Rodrigo ZORRILLA MORALES；
    IPC主号:
    专利说明:

    METHOD FOR DETECTION OF THE OPEN PHASE IN A SYSTEMTHREE PHASE ELECTRIC SECTOR OF THE TECHNIQUE
    The present invention relates to the Method for the Detection of the Open Phase in a Three-Phase Electrical System. This method is applicable to all three-phase electrical configurations, based on the current values measured by the measuring equipment or the resulting current of the current transformers connected in each phase, therefore, we need to know the currents that circulate in each of the three phases. BACKGROUND OF THE INVENTION
    There is currently no recognized method to detect the open phase. Among the types of fault existing in the protection systems, the open phase is not contemplated, although, in the process of a phase-to-ground phase, the transit of said phase to ground is an open phase, in addition, if this phase does not contact with some element connected to earth, it is considered as a lack of phase to earth with high impedance and can be undetected, behaving, therefore, as an open phase. Although this problem is not new, a method for its detection has not yet been developed. Since the event occurred at the Byron nuclear power plant (US), a search for some procedure, method or equipment worldwide has begun. The procedures that are currently being investigated are related to the creation of a new protection relay, for the study, analysis and measurement of the homopolar current or the reverse current. All these investigations have the disadvantage that new technologies have to be developed or precise analyzes and measures have to be made to distinguish between an open phase of a fault, electrical transients or the moment of the system to be protected must be taken into account.
    I quote some investigations or documents related to the open phase:
    • Study of the impact of the loss of a phase on the external power systems of a nuclear power plant -Universidad Pontificia de Comillas ICAI http://www.iit.comillas.edu
    • Diagnosis of a permanent magnet motor through the MEF -Universidad del Valle (Colombia)
    • Open Phase Protection -Altran www.altran-na.com
    • Development and Analysis of an Open-Phase Detection Scheme www.epri.com
    • Open Phase -Duke http://pbadupws.nrc.gov/docs/ML1306/ML13066A708.pdf
    • Single Phase Event NRC Presentation -Exelon Byronhttp://pbadupws.nrc.gov/docs/ML 1306 / ML 13066A 7 41. pdf EXPLANATION OF THE INVENTION
    In a three-phase system the three currents have a lag, if one of the phases opens, then the other two form a closed circuit. The open phase will have a current equal to zero and the other two will equal the value of their currents, their senses will be opposite and will have a 180 ° offset. This event is detected by measuring its currents in each conductor with an RMS measuring device in each phase such as a hook multimeter or through the measurement of the current transformers installed in each phase.
    Another way to detect a three-phase system with an open phase is to observe the resulting waveforms, in this case, the alternating waves of the unopened phases will be symmetrical with respect to the X axis, opposite alternating waves of the same module and with a 180-phase offset °, the wave of the open phase becomes a horizontal with a module equal to zero. This event can be detected with the use of equipment capable of drawing the waveform of the instantaneous current that results from the current transformers placed in each phase, such as an oscilloscope, analyzer or recorder. Using the phasors of the currents a three-phase system with an open phase is also detected, in this case, the phase that is open has a module current vector equal to zero, the unopened phases have vectors in opposite directions of the same module and with a 180 ° offset angle. These conditions can be configured in a protection relay or alarm equipment that directly or indirectly connected to the current transformers of each phase of the three-phase system will be able to detect an open phase event.
    These forms of Open Phase Detection use current measurement equipment, effective (RMS) or instantaneous, in relation to the state of the art currently being investigated, a new technology relay is not required or complex measurements such as homopolar current or inverse, or homopolar or inverse tension. BRIEF DESCRIPTION OF THE DRAWINGS
    To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, a set of drawings is attached as an integral part of said description, where illustrative and non-limiting nature has been represented. next:
    Figure 1.- Shows the conductors of the three-phase system, the open R phase, and the RMS currents of the S and T phases of the same module and opposite directions. Figure 2.- Shows the instantaneous alternating waves that result from an open phase event, the S and T phases form a symmetrical system with respect to the X axis, the open phase R is drawn as a horizontal module line equal to zero. The graph shows a specific open phase event. Figure 3.- Shows the currents in fasorial mode. In a) the 180 ° offset is shown, and in b) its fasorial angles of each vector, whose sum in absolute value is 180 °. PREFERRED EMBODIMENT OF THE INVENTION
    In view of the aforementioned figures, it is observed that this invention is a consequence of the interpretation, observation, understanding, from the measured or resulting currents of the current transformers, concluding whether or not it is in an open phase event .
    In Figure 1, when measuring the currents in a three-phase system, if the value of the RMS current of the R phase is equal to zero, and the value of the RMS current in the equal S and T phases, it will be concluded We are in an open phase event. This is applicable in low voltage and high voltage, in balanced or unbalanced three-phase systems, because the unopened phases form a closed circuit. For example, if in the power supply of a three-phase three-conductor motor, the R phase is open, when measuring the currents of the S and T phases, it is observed that their RMS current values are equal and that the open R phase has a value RMS current equal to zero.
    Figure 2 shows the resulting waveform of a three-phase system with an open phase, the R phase is drawn horizontally for being the phase that has opened, and the S and T phases with an alternating waveform opposite the one of the other and a half-wave or 180 ° offset. This verification can be useful for not starting up a three-phase system that would be with an open phase, or that being in operation has an open phase and we must make the decision to keep it or disconnect it. For example, if we want to transfer from one electrical system to another.
    In Figure 3 of fasorial analysis, as the two previous figures will help us to detect the open phase. If said fasorial condition (fasorial condition: open R phase, therefore, zero vector, closed S and T phases, therefore, opposite vectors of the same module and with a 180 ° offset between them) is configured in a protection relay this It will trigger the protections and / or send alarm signals in case of open phase. Applied to an auxiliary power system connected to a vacuum transformer (without load), the currents are due to the load of the transformer itself, therefore, if the R phase opens, the S and T phases meet the phasor condition, firing the switches and / or sending an alarm signal. These currents multiplied by their voltage give us their powers per phase, the open phase being zero and of equal powers the non-open phases.
    The three figures are applicable to any open phase event, it will only depend on how the plant is configured or which of these forms of open phase detection is more convenient and in all of them you can use a visual or audible alarm element, shooting of protections or system locking with open phase.
    权利要求:
    Claims (2)
    [1]
    1. Method for the detection of the open phase in a three-phase electrical system, is intended to detect an open phase in a three-phase electrical system, starting from the
    5 measurement of the current in each phase or of the current obtained in the secondary of each of the current transformers, which consists of: -detection of the disturbance in the three-phase electrical system -comparison of the measurements of the values of RMS current, being the phase
    open equal to zero and the other two non-open phases equal and non-zero 10 -generation of visual or audible alarm signals, protection trigger signals or system locked signals with open phase. Figure 1.
    [2]
    2. Method for detecting the open phase according to claim 1, characterized
    15 because in its instantaneous waveform of each of the phases, the open phase will have a horizontal wave with zero amplitude and the other two unopened phases will have alternating waves, opposite, of equal amplitude and with a half-wave offset (180 °), forming a symmetrical system with respect to the X axis. Figure 2.
    the detection of the open phase according to claim 1, characterized in its fasorial form of each of the phases, the open phase is a vector and the other two unopened phases are opposite vectors of the same module.
    类似技术:
    公开号 | 公开日 | 专利标题
    ES2734214T3|2019-12-04|Method to detect an open phase condition of a transformer
    CN101325331B|2011-04-06|Method for implementing element for measuring distance between phases without relevance to load current and ground resistance
    CN101325330B|2011-04-06|Method for implementing earthing distance measurement element
    ES2535750T3|2015-05-14|Directional detection of a defect, particularly in a neutral or compensated neutral network
    Yu et al.2015|Break-point diagnosis of grounding grids using transient electromagnetic apparent resistivity imaging
    Zhu et al.2017|On-site non-invasive current monitoring of multi-core underground power cables with a magnetic-field sensing platform at a substation
    Pinpart et al.2009|Experimental comparison of UHF sensor types for PD location applications
    CN101325329A|2008-12-17|Method for implementing earthing distance measurement element based on negative sequence fault current component
    CN101325332B|2010-06-09|Method for implementing element for measuring earthing distance without relevance to load current and ground resistance
    Ferreira et al.2010|A noninvasive technique for fault detection and location
    US9568535B2|2017-02-14|Methods for detecting an open current transformer
    Kletsel et al.2014|Protection of busbar based on reed switches
    Zhu et al.2019|Fault classification of power distribution cables by detecting decaying DC components with magnetic sensing
    Fan et al.2021|Faulty phase recognition method based on phase-to-ground voltages variation for neutral ungrounded distribution networks
    ES2675010B1|2019-04-09|Method for the detection of the open phase in a three-phase electrical system.
    RU2263333C2|2005-10-27|Method for detection of disruptions of insulating cover of underground pipeline
    Li et al.2011|Robustness analysis of magnetic sensor arrays for current sensing
    Ferreira2007|Fault location for power transmission systems using magnetic field sensing coils
    Kane et al.2010|Field results of monitoring partial discharges on in-service large power transformers
    Muddebihalkar et al.2015|Analysis of fault location algorithm for transmission line protection based on synchronized phasor measurement
    Koo et al.2010|Investigation of partial discharge phenomena in HTS transformer adopting different type of sensors
    Lei et al.2016|Additional low frequency signal measurement method of insulation resistance about mine cable
    Lackey et al.2017|Low-cost magnetometer sensing system for detecting geomagnetically induced currents in transmission lines
    Anane et al.2021|Non-contact measurement of traveling wave of overhead transmission line
    Isa et al.2009|Comparative study of on-line three phase PD monitoring systems for overhead covered conductor distribution lines
    同族专利:
    公开号 | 公开日
    ES2675010B1|2019-04-09|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CN2565183Y|2002-07-17|2003-08-06|赵奎林|Under-voltage open-phase monitor|
    法律状态:
    2018-07-05| BA2A| Patent application published|Ref document number: 2675010 Country of ref document: ES Kind code of ref document: A1 Effective date: 20180705 |
    2019-04-09| FG2A| Definitive protection|Ref document number: 2675010 Country of ref document: ES Kind code of ref document: B1 Effective date: 20190409 |
    2019-09-19| FA2A| Application withdrawn|Effective date: 20190913 |
    优先权:
    申请号 | 申请日 | 专利标题
    ES201700011A|ES2675010B1|2017-01-03|2017-01-03|Method for the detection of the open phase in a three-phase electrical system.|ES201700011A| ES2675010B1|2017-01-03|2017-01-03|Method for the detection of the open phase in a three-phase electrical system.|
    [返回顶部]