JP4887322B2 - Power system phase detection system - Google Patents

Description

  The present invention relates to a monitoring system for the purpose of grasping the phase state of voltage and current in a power system, and in particular, a large number of measuring slave stations are provided at the end of an arbitrary low-voltage system, By having the function of correcting and calculating the measurement information of these slave stations, it is a phase detection system for the power system to grasp the phase distribution state of a wide range of the power system.

  In power system monitoring and observation, a system has been established for a long time to grasp the power flow state of the entire system using voltage measurement and current measurement. After collecting the voltage value measured by PT (Potential Transformer) and the current value measured by CT (Current Transformer) in the communication network, the direction and voltage of the effective reactive power at each point in the system network using state estimation technology Estimate the distribution and phase states.

  In recent years, in addition to these observation techniques, techniques for directly observing phase information using a phase detector PMU (Phasor Measurement Unit) are being established. This is a technology for observing the phase state of voltage / current with high accuracy by utilizing a highly accurate time synchronization technology represented by GPS. In the conventional monitoring and observation method as described above, the phase information is an object to be estimated, but the phase information has become a direct observation object due to the appearance of the PMU.

  Considering the above-described phase detector, new applications are being studied. For example, a system has been proposed in which a phase detection device is provided especially for the backbone system portion and used for stability analysis or stability control of the entire power system (Patent Documents 1 and 2). Compared to the conventional method based on state estimation calculation, phase information can be obtained with high accuracy and high speed, and it is considered that highly effective stability control is possible.

JP 2006-2111830 A JP 2006-109545 A

  Conventionally, in an application using a phase detection device for the purpose of stability control or the like, the phase detection device is directly installed at a system point where phase detection is desired. For example, in order to detect a voltage phase at a main main substation, a phase detection device PMU is installed as a function of the protection control device panel of the substation.

  When installing the phase detection device based on such a concept, it is difficult to install the phase detection device at many points. This is because the current phase detectors can be installed at substations, and there are restrictions such as limitations on installation space and installation costs due to restrictions on installation substations. It is difficult to install a phase detector for a wide range of power systems from the upper system to the lower system.

  Therefore, the present situation is based on observation information obtained from phase detectors installed at only a few critical points, generally only a few of the backbone systems in the power system, and applications that can be realized with it are considered. I can say.

  It is an object of the present invention to realize various applications using phase information by solving the problems relating to the installation location of the phase detection device.

  A phase detection system composed of a master station and slave stations is introduced. First, at each point where phase measurement is desired, a slave station for phase detection is installed at the low-voltage end of the customer in the vicinity. Since it is installed at the end of the low voltage, it can be installed at any place without power outage work. However, the phase value measured at the slave station has a deviation (error) from the phase value at the destination point. The master station has a function of correcting and calculating this deviation.

  By configuring a phase detection system composed of a master station and a slave station having the above functions, phase information can be grasped in a wide range of power systems. It is possible to grasp not only the phase information at the main substation measured by the conventional phase detection device but also the estimated phase information at a wide range of points to the distribution system.

  Thus, the phase information obtained by direct measurement or estimation calculation can be used as input information for various distribution automation applications. For example, by comparing the phase values at multiple points, it is possible to realize a connection phase confirmation / management function for each customer, an isolated operation detection (estimation) function for a distributed power source, a synchronization confirmation function when a loop is turned on, etc. Can do.

  In addition, by arranging a large number of slave stations at the end of the system, an application that has not been possible in the past can be realized at low cost. By estimating the tidal current state from the phase information, it is possible to link with an application that takes the tidal current state as an input. For the purpose of minimizing loss loss of the transmission and distribution system, it is possible to construct a system configuration planning support system and an online control system for various phase adjusting facilities.

  According to the present invention, by configuring a phase detection system composed of a master station and a slave station, it becomes possible to grasp phase information over a wide range of power systems, and various applications using phase information can be realized. .

  Embodiments of the present invention will be described below with reference to the drawings.

(Example)
As an embodiment, a case where the present invention is applied to a phase detection system that handles phase information of the entire system in a power system will be described.

  The overall configuration of the system is shown in FIG. The system includes a master station 0101 and a plurality of slave stations 0102.

  First, the slave station 0102 is provided with voltage phase detection means 0104 connected to a power line 0103 through which an alternating current is applied. When detecting the voltage phase, the time detection unit 0105 provides the voltage phase detection unit 0104 with time information that is time-synchronized with high accuracy in units of microseconds using GPS or the like. The voltage phase detection unit 0104 generates a phase value data list that is observed at a sampling interval of a fixed period, based on the time synchronized with the standard time.

  Next, the phase data observed in this way is prepared for transmission to the master station via the communication network. First, from the individual identifier storage unit 0106, identification information that can uniquely determine which slave station is the observed information is obtained. After that, in the master station transmission / reception information creating unit 0107, a message to be transmitted / received to / from the master station is generated in conformity with a prescribed protocol, and transmitted to the master station 0102 via the communication function 0108. The communication line here is a communication means that connects to the open Internet via FTTH, ADSL, power line carrier (PLC), wireless LAN, etc., and is safe in a wide area using standard secure communication technology such as SSL. Communication is possible. When only the phase information is transmitted, it is considered that the necessity of information concealment is low unlike information in which personal information such as power consumption can be estimated, and thus the public communication network can be used.

  On the other hand, the master station 0103 collects measurement phase information with the communication function 0109 from the above slave stations 0102 installed in a wide range. The collected information is confirmed and inspected from which slave station, and valid information is stored in the measurement phase value database 0110. As will be described later, it is assumed that these measurement phase values include errors. Therefore, the master station performs a process for correcting this.

  First, the estimated value of the power consumption at the measurement point of each slave station is obtained from the power consumption profile database 0111 for each consumer. Using this, the process of calculating the estimated phase value from the measured phase value is performed by the phase value correction estimating unit 0112. The details of the correction calculation will be described later. The calculated estimated phase value is stored in the estimated phase value database 0113 together with the position information of the power system. The estimated phase value database 0113 can permit access from the outside that can be trusted, and various applications can execute calculation processing using the same phase information.

  Next, an embodiment in a communication environment different from that in FIG. 1 will be described with reference to FIG. In the embodiment of FIG. 1, the description has been given of the case where each of the master station and the slave station has a communication unit and realizes wide area communication through an open Internet connection or the like. In FIG. 2, wide-area communication is realized using a communication means provided in a remote metering system (intelligent power meter) of consumer power consumption, assuming that the slave station is installed near the customer facility. Examples will be described.

  The system of the embodiment of FIG. 2 also includes a master station 0201 and a plurality of slave stations 0202 as in the embodiment of FIG.

  First, the slave station 0202 includes voltage phase detection means 0204 and time detection means 0205 connected to the power line 0103 as in the embodiment of FIG. In addition, the transmission / reception message is generated by the individual identifier storage unit 0206 and the parent station transmission / reception information creation unit 0207 when transmitting to the parent station, as in FIG.

  Here, in this embodiment, a communication system included in the remote meter reading system is used. The intelligent power meter 0208 is a power consumption detection device that uses the same power line as the phase detection destination power line 0203 as an observation target. There are such a plurality of power meters 0208 and a meter-reading center 0209 that collects remote meter-reading information therefrom, and has a communication system between the power meters. In the wattmeter 0208, the power consumption is measured by the power consumption measuring means 0210, a message is generated by the additional information adding function 0211 based on this, and transmitted by the communication function 0212 of the wattmeter. In the center 0209, the information received by the communication function 0213 is stored in the power consumption measured value database 0214 for each consumer. The communication line here is a closed communication network that depends on the remote meter reading system and can be used only by operators engaged in meter reading work using technologies such as PLC and wireless communication.

  A procedure in which such a remote meter reading system and the phase detection means cooperate will be described. First, the slave station 0202 transfers the message generated by the master station transmission / reception information creating unit 0207 to the wattmeter 0208. In the message creation in the additional information addition function 0211 of the power meter, the transmission message is generated by adding the measurement phase information transferred from the 0207 in accordance with the information on the power consumption. In the meter reading center 0209 that has received this, the measurement phase information is separated from the information on the amount of power used, and is transferred to the master station 0201. The master station 0201 stores this in the measurement phase value database 0213. Further, the phase value correction estimation unit 0217 does not use profile information as in the embodiment of FIG. 1, but acquires measurement information from the consumer-specific power consumption measurement value database 0214 to obtain the consumer-specific attribute database 0216. The correction calculation described later is performed together with the above information. The calculated estimated phase value is stored in the estimated phase value database 0218 together with the position information of the power system, as in the embodiment of FIG. 1, and various applications execute calculation processing using the same phase information. become able to.

  As described above, the phase detection device is composed of a master station and a plurality of slave stations. In the case of collecting information by a unique communication function between the master station and the slave station, a functional configuration as in the embodiment of FIG. 1 is obtained. On the other hand, in the case of realizing information collection in cooperation with the communication function of the remote meter reading system, the configuration is as shown in the embodiment of FIG. In any embodiment, the location of the slave station is not limited.

  As a place where the conventional phase detection device is installed, the phase detection device is directly installed at a system position where phase detection is desired. For example, as shown in FIG. 3, the object is to detect a phase at a transmission point 0302 of a line at a substation 0301. In this case, a phase detector is installed as a function of the protection control device panel of the substation 0301. It is difficult to install phase detectors at many points because it can only be installed at substations, and the number of substations that can actually be installed is limited due to restrictions on installation space and installation costs. Therefore, the phase detector is arranged only at a very limited important point. In general, it is installed in the main system of the power system.

  On the other hand, the installation location of the slave station of the present invention is not restricted. For example, in FIG. 3, when measuring a point 0303 for which phase measurement is desired, a phase detection slave station 0304 is installed at a low-voltage end of a nearby consumer. Since it is installed at the end of the low voltage, it can be installed at any place without power outage work. However, as described above, there is a deviation (error) between the phase value measured by the slave station 0304 and the phase value at the target point 0303. This deviation is caused by the deviation of the measurement point, and is generated according to the impedance of the pole transformer 0305, for example. In the present invention, the estimated phase value of the point 0303 is calculated from the measured phase value of the slave station 0304 by correction calculation (corresponding to the phase value correction estimation means in FIGS. 1 and 2) described later in the master station. is doing.

  By using a phase detection system having such a function, it is possible to grasp phase information over a wide range of power systems. As shown in FIG. 4, in grasping the phase state of the commercial power system 0401, not only the measurement phase information of the conventional phase detection device provided at the transmission point 0402 but also the information obtained from the slave stations 0403 to 0405, the point 0406 The estimated phase information of 0408 can be grasped.

  Next, an outline of correction calculation in the master station will be described with reference to the flowchart of FIG. As described above with reference to the phase value correction estimation means in FIGS. 1 and 2, the estimated phase value is calculated using the measured phase value obtained from the slave station and the power consumption profile or power consumption measurement value for each consumer. It becomes calculation processing to do.

  First, a phase difference correction process 0501 is performed. In this correction process, the deviation caused by the impedance existing between the slave station installation point and the measurement destination point is corrected. The contents of this calculation can be expressed as a voltage vector diagram as shown in FIG. Assume that a voltage vector Vr (0601) is observed as an arbitrary phase voltage. Considered simply, this phase voltage Vr has a phase difference 0604 due to Z · Ir (0603) due to the impedance Z as described above, compared to the phase voltage Vs (0602) at the observation destination. Can be considered. Therefore, in this phase difference correction process 0501, in order to correct the phase difference 0604, a process of estimating the phase voltage Vs (0602) at the observation destination point is performed using the estimated value of the current vector Ir.

  Assuming that the current vector Ir has a magnitude of current corresponding to the power consumption defined in the profile or the power consumption observed by the power meter, a vector orthogonal to Vr is assumed. First, when using a profile, necessary information is acquired from a database (database 0111 in FIG. 1). This database has a structure as shown in FIG. For each slave station, an individual identifier 0701, type information 0702 of equipment such as a transformer to be connected and its impedance 0703 are stored. In addition, information 0704 indicating the location of the slave station in the system diagram and further, power consumption profile type information 0705 defined for each consumer are stored.

  Each profile identifier described in the power consumption profile type 0705 indicates one piece of profile information. The contents are shown in FIG. Data 0803 indicating the behavior of the power consumption of the day is defined for the horizontal axis 0801 in units of 24 hours considering the season and the day type, and the vertical axis 0802 indicating the power consumption for each hour. Profile information is described for each of the profile identifiers described in the database of FIG.

  With the configuration as described above, impedance information is obtained from the database of FIG. 7, and the phase value of the voltage vector at the measurement destination point is estimated by calculating the current amount from the power consumption amount extracted from the profile. It is possible to calculate. In addition, when using observed values, the voltage at the measurement destination point is calculated by performing the same calculation using the power consumption value directly observed with a power meter, not the assumption of power consumption by the above profile. The vector phase value can be estimated and calculated.

  Next, a connection phase determination process 0502 is performed. The phase values observed at the respective slave stations include those whose measurement target is the phase voltage of the U phase, the V phase and the W phase, and those whose measurement targets are the respective line voltages. The voltage to be measured depends on the difference in the wiring system of the transformer existing between the low voltage system where the slave station is installed and the upper system. Therefore, this determination process determines to which connection phase the measurement data of each slave station corresponds.

  First, the concept of the process will be described with reference to FIG. For convenience, the phase value data 0902 observed at an arbitrary slave station is plotted on an axis between 0 degrees and 360 degrees, assuming that the phase 0901 of the U phase is 0 degree. When such a conceptual arrangement is used, in the phase detection in the power system network in the vicinity area, all plots can be grouped into either the phase voltage of the U phase, the V phase, the W phase, or the respective line voltages. In an actual power system configuration, the phase difference between a plurality of locations in the vicinity is not as high as 10 degrees, so that it can be considered that there is no possibility of erroneous grouping ideally. The connection phase is determined according to this concept.

  Actual processing is performed based on the concept shown in FIG. The phase is plotted on the horizontal axis 1001 and the frequency of occurrence is plotted on the vertical axis 1002. On this figure, the determination regarding the phase voltage of the U phase is performed. First, a range 1004 from which a predetermined likelihood is taken is defined with the phase angle used as the reference of the previous U phase as a reference 1003. Actually, a threshold having a magnitude of about ± 10 degrees is adopted as the likelihood. A measurement value 1005 that deviates from this range 1004 can be determined as an abnormal measurement value that has occurred for some reason. In this system, such an abnormal measurement value is excluded from the calculation target. On the contrary, those remaining in the range 1004 are grouped and handled as measurement phase values corresponding to the U-phase phase voltage. In addition, in the phase range inverted by 180 degrees from the reference value of the U-phase phase voltage, the measurement phase value group that is grouped in the same way as the above process is considered to correspond to the U-phase phase voltage. Such a measurement phase value group is inverted by 180 degrees and then added to the U-phase phase voltage group. Finally, a phase value calculated by statistical processing such as arithmetic simple averaging is adopted as a new U-phase reference value for the group of measurement phase value groups of finally grouped U-phase voltages.

  By performing such a connection phase determination process for each of the phase voltage of the U phase, the V phase, the W phase, or the line voltage, all the measured phase values are classified into any group or abnormal. A determination is made as to whether it is excluded as a value.

  By configuring the phase detection system as described above, phase information can be grasped in a wide range of power systems. By providing the phase information obtained here to an application for distribution monitoring control, various applications can be achieved.

  An online connection phase management system will be described as a first application example. In this system, when electrical work is carried out in the vicinity of a customer connected along the distribution line or with a lead-in line, information on the phase to which the power facility is connected by the local worker for the power facility at a specific point The purpose is to get online.

  In FIG. 11, a method of applying the phase detection system to the connection phase management system will be described. There is an upper voltage class UVW phase wire 1101 and a lower voltage class lead-in wire 1102 drawn from the wire. The connection method 1103 during this period is confirmed using online phase data. A slave station 1105 and a slave station 1106 are connected to the phase detection system master station 1104 via communication, and phase information at these points can be obtained. The master station 1104 provides the phase information to the connection phase management system 1107. Here, when the worker 1108 is planning to work on the power equipment in the vicinity of the slave station 1105, the connection phase is inquired via the work terminal. The connected phase management system 1107 searches for a nearby slave station 1105 from the location information of the terminal and displays this phase information on the screen. At the same time, the phase information by the slave station 1106 in the close upper voltage class is compared and displayed. By this display, the worker 1108 can determine online to which phase the power equipment planned for work is connected.

  A distributed power management system will be described as a second application example. The purpose of this system is to monitor the operating status of the distributed power supply connected to the distribution line, and at the same time to detect and prevent isolated operation of the distributed power supply when the distribution line goes into a power outage. . However, the interconnection device of each distributed power source is provided with a function of performing local operation detection locally in accordance with the interconnection guidelines of the electric power company that owns the distribution line. The independent operation monitoring by the distributed power management system operates separately to reinforce this.

  In FIG. 12, a method of applying the phase detection system to the distributed power management system will be described. The distribution line 1201 is provided with a plurality of slave stations 1202 to 1204 of the phase detection system for each section. There is also a master station 1205 connected to these via a communication line. Here, the distributed power source 1206 is operating in communication with the distribution line 1201. The distributed power source is monitored and controlled by the distributed power management system 1207 via a communication line. The distributed power management system 1207 receives information related to the phase state of the distribution line 1201 from the master station 1205. While monitoring this phase state, monitoring of the isolated operation prevention of the distributed power source 1206 is performed. Specifically, the phase state of the slave station 1204 belonging to the section in which the distributed power source 1206 is linked is monitored in time series with the phase state of the other section. If the difference between these phase states changes abruptly so as to greatly exceed a predetermined reference, it can be determined that the same section has been disconnected. In response to this, an operation stop command is transmitted to the distributed power source 1206. By such an operation, it is possible to prevent an isolated operation at the time of power system power failure.

  As a third application example, an advanced case of loop injection control will be described. For example, for the purpose of eliminating system faults or improving operational efficiency, the distribution automation system performs loop injection to change the configuration of sections in the distribution system. For the phase confirmation work at this time, a phase detection system is used.

  In FIG. 13, a method in which the distribution automation system performs a loop switching operation in cooperation with the phase detection device will be described. A plurality of slave stations 1302 to 1304 of the phase detection system are connected to the distribution line 1301, and the master station 1105 collects phase information via a communication line. On the other hand, the center server 1306 of the power distribution automation system performs monitoring control of the switch 1307 and the switch 1308 via a dedicated communication line. The power distribution automation system attempts to open the switch 1307 after the switch 1308 is turned on to configure a loop system once as a system switching operation. At this time, first, the center server 1306 receives the phase information on the distribution line from the master station 1305 of the phase detection system. Based on this information, the phase difference between the two sections sandwiching the switch 1308 is scrutinized. Here, the phase difference is calculated from information of the slave station 1303 and the slave station 1304. When it is confirmed that this phase difference is less than the allowable range specified in the business procedure, the center server 1306 transmits a closing command value to the switch 1308 and then transmits an opening command to the switch 1307. To do. On the contrary, when the phase difference is larger than the allowable range, the loop insertion operation is stopped. By such an operation, the phase can be confirmed when the system is switched. In addition, the same mechanism can be used to check the phase when the switch is turned on when the distributed power source is connected.

  As a fourth application example, an application in a power flow monitoring screen display of the system monitoring system will be described. The purpose of this system is to present the voltage distribution, phase distribution, and power flow state in the power system graphically to the operator as a function of a distribution automation system.

  In FIG. 14, a method of applying the phase detection system to the tidal current monitoring screen will be described. The screen 1401 is a screen that displays the power flow state of the power system for the time section designated by the date / time selection operation 1402 or the latest time selection operation 1403. This system monitoring system receives phase information of the power system from the phase detection system and displays it on the screen. On the screen 1401, the phase information estimated by the phase detection system for the power line 1404 is displayed 1405 at a plurality of points. In addition, voltage value information 1406 obtained from another system is also displayed. Further, the display 1407 also displays values obtained by estimating and calculating active power / reactive power flowing between the points. This value is calculated using voltage information and phase information. For example, when a tidal current flowing between the points A and B is considered, the effective power P = VaVbsinδ / X, ineffective at the voltage Va at the point A, the voltage Vb at the point B, the reactance X between the two points, and the phase difference δ. Estimation calculation is performed by a simple expression such as power Q = (VaVbcos δ−Vb 2) / X. By such an operation, a tidal current monitoring screen is generated, and information easy to understand for the operator can be provided.

  Finally, the business procedure regarding installation of the slave station in the phase detection system of the present invention will be described. These slave stations may be installed in facilities owned by customers. While the phase detection system contributes to stable operation of the electric power system, there are few direct merit due to the installation of the slave station from the viewpoint of the consumer. Therefore, in order to advance the arrangement of slave stations over a wide area, it is conceivable to provide financial incentives to consumers.

  Therefore, the phase detection system master station constantly monitors whether each slave station is performing an effective operation. The presence / absence of operation of each slave station is determined using an individual identifier unique to the slave station as a determination material. For the slave stations performing the effective operation, the installed customer information is delivered to the charge management system. In the charge management system, services such as power charge discounts are provided to consumers. With such a mechanism, the customer can get an incentive to install a slave station, and it is also possible to promote the wide introduction of the phase detection system.

  In a conventional phase detection device, a phase detection device is installed as a function of the protection control device panel at a substation near the system location where phase detection is desired. In this case, it is difficult to install the phase detectors at many points because it can only be installed at the substation, and the substations that can actually be installed are limited due to installation space restrictions and installation cost restrictions. Therefore, the phase detector is arranged only at the important point.

  On the other hand, when a phase detection system composed of a master station and a slave station having the functions described above is configured, it is possible to grasp phase information over a wide range of power systems. It is possible to grasp not only the phase information at the main substation measured by the conventional phase detection device but also the estimated phase information at a wide range of points to the distribution system.

  The estimated phase information obtained in this way can be used as input information for various distribution automation applications. By using the phase value itself, it is possible to realize a connected phase confirmation / management function for each customer, an isolated operation detection (estimation) function of a distributed power source, a synchronization confirmation function when a loop is turned on, and the like. In addition, by arranging a large number of slave stations at the end of the system, an application that has not been possible in the past can be realized at low cost.

  Furthermore, by estimating the tidal current state from the phase information, it is possible to cooperate with an application that receives the tidal current state as an input. For the purpose of minimizing loss loss of the transmission and distribution system, it is possible to construct a system configuration planning support system and an online control system for various phase adjusting facilities.

The functional block of the phase detection system of this invention. The functional block of the phase detection system of this invention (when it cooperates with a remote meter-reading system). Slave station installation location (example). Explanation on the system diagram regarding the location of slave stations. Phase value correction estimation calculation flow in the master station. Phase value correction calculation contents (example). Structure of power consumption profile database by customer (example). Day pattern of power consumption profile by customer (example). Concept of connection phase judgment. Content of connection phase determination processing (example). Application of phase detection system to connected phase management. Application of phase detection system to distributed power management. Application of phase detection system to loop injection control. Tidal current monitoring screen (example).

Explanation of symbols

0101 Master station 0102 Slave station 0103 Power line 0104 Voltage phase detection means 0105 Time detection means 0106 Individual identifier storage means 0107 Master station transmission / reception information creation means 0108, 0109 Communication function 0110 Measurement phase value database 0111 Consumer power consumption profile database 0112 Phase value Correction estimation means 0113 Estimated phase value database

Claims (8)

In a system for detecting the phase of AC voltage and AC current in a power grid,
It is composed of one or more slave stations equipped with a phase detection device equipped with time synchronization means, and a master station equipped with a system component facility of the power system and a database storing impedance information of the component facility. ,
The master station collects the phase value measured by the phase detector of the slave station, performs correction calculation of the measured phase value using impedance information of the component equipment, and calculates the estimated phase value A phase detection system for a power system, which is stored in a database.   2. The phase detection system for a power system according to claim 1, wherein the phase value is collected by providing communication means in the master station and the plurality of slave stations.   In Claim 2, the profile which prescribed | regulated the statistical pattern about the electric energy which the said sub_station | mobile_unit comprises the point which carries out the phase measurement in the database which the said main station comprises, and stores the said profile for the said phase value correction calculation. A phase detection system for an electric power system characterized by being used.   2. The remote station according to claim 1, wherein the slave station is connected to a power meter having a remote meter reading function and transmits a measurement phase value to the master station using a remote meter reading communication network, and then the master station performs remote meter reading. A phase detection system for a power system, wherein the correction calculation is performed using a measured phase value collected through the system and a passing power amount at a phase measurement point of the slave station.   The phase information is externally provided for the purpose of the power system power monitoring system performing estimation calculation of the power flow status by enabling read access to the estimated phase value database from the power system power flow monitoring system according to claim 1. A phase detection system for an electric power system.   In Claim 1, by enabling read access to the estimated phase value database from the distributed power management system, the distributed power management system answers online whether or not the distributed power facility is operated independently at a specific point. A phase detection system for a power system, characterized in that phase information is provided externally for the purpose.   The purpose of claim 1 is to enable online access to information on phases connected to power equipment at a specific point by enabling the read access to the estimated phase value database from the connection phase management system. A phase detection system for a power system, characterized in that phase information is provided externally.   The phase information according to claim 1, wherein the distribution automation system can automatically perform phase synchronization determination at the time of switching-on control by enabling read access to the estimated phase value database from the distribution automation system. A phase detection system for a power system, characterized in that the system is provided externally.

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