KR101601164B1 - Phase discrimination apparatus and method of electric power system - Google Patents

Abstract

A power system phase discrimination apparatus according to the present invention comprises: a master discrimination unit which performs a tap control of a transformer by transmitting a request for the tap control to the transformer including a tap for a voltage control; and a slave discrimination unit which calculates an average of voltages for each phase before controlling the tap of the transformer, measures a voltage after the tap is controlled by the transformer to calculate a standard deviation and an average of the measured voltages, and discriminates each phase of the transformer matched to each phase of electric equipment by using the average and the standard deviation obtained before and after the tap control of the transformer.

Description

[0001] PHASE DISCRIMINATION APPARATUS AND METHOD OF ELECTRIC POWER SYSTEM [0002]

[0001] The present invention relates to a power system phase discrimination apparatus and method, and more particularly, to a power system phase discrimination apparatus and method in which a voltage tap of a transformer is adjusted to measure a voltage of each phase, And more particularly, to a power system phase discrimination apparatus and method for discriminating an image of a system.

The power system supplies three phases of power with a 120 degree phase difference from each other. Three - phase power with 120 - degree phase difference can efficiently operate a three - phase motor because it has electromagnetic characteristics that can generate a rotating field.

The power of these three phases is divided into A, B, and C phases (or R phase, S phase, and T phase) on three voltage lines, and is transmitted to the final electric user through the power transmission line. For a number of reasons, these awards must be distinguished and well managed. Here are some important reasons.

First, when electrical connections are made between different phases, arcing occurs like a flame and a failure occurs in the power system.

Second, in the case of a three-phase motor that occupies most of the three-phase load, the order of these phases is reversed and the direction of rotation of the motor is reversed when connected.

Third, the power of three phases should be controlled to be balanced at all times. However, the same principle as maintaining the frequency by the generator and the load being balanced is that the size of the single phase load connected to each phase must be balanced to some extent. Loads should also be managed by phase. Especially, the transformer is very important because it needs to adjust and control the size of the voltage and the capacity of the current by balancing the load and balance for each phase.

In terms of time, since the difference between phases is only 5.56ms in 60Hz system, it is necessary to use GPS (Global Positioning System) which can precisely synchronize time to distinguish phases, A high-performance microprocessor must be installed in each device. Although there is a portable phase measurement device, it is highly probable that the original phase will change due to maintenance work and new facility construction. Therefore, it is managed as a relative image because it can not be managed as an absolute image in the field. That is, it is impossible to know which wire is A, B, or C, but it is only agreeing that the wires are physically connected to each other. However, in this method, it is difficult to know how much of the loads connected to each phase are connected to each other in the case of a three-phase transformer.

As smart grid technology has recently been developed, the importance of phase management of power devices and loads of single phase connected to the power distribution system is emphasized, but it is not applicable because it takes a lot of cost to implement functions required for phase discrimination. In addition, conventionally, there is a problem in that it requires a high-precision part for injecting a separate signal for accurate discrimination, or for precise time synchronization and frequency division of GPS.

The background art of the present invention is disclosed in Korean Patent Laid-Open Publication No. 10-2008-0044975 (May 22, 2008).

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a voltage transformer that measures voltage of each phase by adjusting a voltage tap of a transformer, compares a voltage before the voltage tap adjustment with a voltage after the adjustment, And to provide a power system phase discrimination apparatus and method for discriminating an image of a power system.

It is another object of the present invention to provide a power system phase discrimination apparatus and method which can accurately discriminate each phase of an electric system in a power system at a low cost and can always maintain the integrity of a phase coincidence during power system operation.

Another object of the present invention is to easily identify the phases of the electric equipment in the power system so as to easily perform the load management on the basis of them, and to perform the optimum management of the phase transformer and the optimum voltage management for the different high voltage distribution lines And to provide a power system phase discrimination apparatus and method for enabling the power system phase discrimination.

It is another object of the present invention to provide a power system phase discrimination apparatus and method which can easily perform load management and line management even if there is a large single phase load distribution such as a rural / rural transmission line with a long power distribution line.

A master discrimination apparatus for a power system according to an aspect of the present invention includes a master discrimination device for requesting a tap adjustment to a transformer having a tap for voltage adjustment to perform tap adjustment of the transformer; And calculating an average value of voltages for each phase before adjusting the taps of the transformer, calculating an average value and a standard deviation of the measured voltages by measuring a voltage after the tap is adjusted by the transformer, And a slave discriminating device for discriminating each phase of the electric equipment by using an average value and a standard deviation after the past and the adjustment.

In the present invention, when the master discrimination apparatus is requested to perform the job for each discrimination from the slave discrimination apparatus, the master discrimination apparatus performs time synchronization with the slave discrimination apparatus and delivers a discrimination task preparation command to the slave discrimination apparatus .

In the present invention, the slave discrimination device may include: a measuring unit for measuring voltages before and after adjustment of the tabs provided in the transformer; Calculating an average value and a standard deviation of the voltage before and after the tap adjustment measured by the measurement unit and generating phase matching information that determines each phase of the electric equipment using the average value and the standard deviation of the voltage before and after the tap adjustment A comparison operation unit; A storage unit for storing the voltage measured by the measuring unit, the average value and the standard deviation of the comparison operation unit, and storing the phase matching information according to the result of the phase determination; And a communication device for performing time synchronization with the master determination device and measuring the voltages before and after the tap adjustment by the measurement section and then determining each phase of the electrical equipment through the comparison operation section, And a controller for storing the image matching information generated by the image matching unit in the storage device.

In the present invention, the comparison operation unit measures a plurality of voltages at predetermined measurement time intervals during a predetermined buffering time before the tap adjustment, calculates an average value and a standard deviation of the measured voltage, And the phase of the transformer is smaller than the value obtained by multiplying the voltage by the voltage per tap.

In the present invention, the comparison operation unit may calculate a value obtained by subtracting a value obtained by multiplying the number of times of tap adjustment by the voltage magnitude per tap from the average value of the voltages after tap adjustment for each phase of the transformer by a voltage and a standard deviation before tap adjustment for each phase of the transformer And determines each phase of the transformer in accordance with the discrimination result.

The power system phase discrimination method according to one aspect of the present invention is characterized in that the slave discrimination apparatus measures a plurality of voltages at predetermined measurement time intervals during a predetermined buffering time, calculates an average value and a standard deviation of the measured voltages, Communicating to the device that the phase-specific preparation is complete; When the slave discrimination device is ready for phase determination, the master discrimination device requests a tap adjustment for voltage adjustment to the transformer; Performing a tap adjustment for voltage adjustment according to a tap adjustment request of the master determination device; When the tap adjustment is performed by the transformer, the master determination device transmits a command for starting a task by phase to the slave determination device; And the slave discriminating device measures an average value and a standard deviation of the voltage after the tap adjustment of the transformer in accordance with the phase discrimination start command and calculates an average value and a standard deviation of each of the electric equipments And determining the phase of the image.

The present invention is characterized in that the master discrimination apparatus performs time synchronization with the slave discrimination apparatus and transmits a discrimination task preparation command to the slave discrimination apparatus.

In the present invention, the step of discriminating each phase of the electrical equipment is characterized by discriminating each phase of the electrical equipment when a value obtained by quadrupling the standard deviation is smaller than a value obtained by multiplying the number of taps and the voltage per tap.

In the present invention, the step of discriminating each phase of the electrical equipment may include calculating a value obtained by subtracting a value obtained by multiplying a tap adjusting frequency and a voltage per voltage by an average value of voltages after tap adjustment for each phase of the transformer, Determining whether each of the phases of the electric equipment is included in the range of the condition set through the average value and the standard deviation, and discriminating each phase of the electric equipment according to the discrimination result.

According to another aspect of the present invention, there is provided a power system phase discrimination method comprising the steps of: when a measured voltage exceeds a predetermined range, transmitting a tap adjustment plan to a master discrimination apparatus; Transferring a task to be set by task to the slave determination device according to the tap adjustment plan; The slave discriminating device measures a plurality of voltages at predetermined measurement time intervals during a predetermined buffering time according to the discrimination task preparation command, calculates an average value and a standard deviation of the measured voltages, Communicating that the discrimination preparation is completed; When the slave discrimination device is ready for phase determination, the master discrimination device requests the transformer to adjust the tap; Performing a tap adjustment for voltage adjustment according to a tap adjustment request of the master determination device; When the tap adjustment is performed by the transformer, the master determination device transmits a command for starting a task by phase to the slave determination device; And the slave discriminating device measures an average value and a standard deviation of the voltage after the tap adjustment of the transformer in accordance with the phase discrimination start command and calculates an average value and a standard deviation of each of the electric equipments And determining the phase of the image.

In the present invention, the master determining device may further include a step of performing time synchronization with the slave discriminating device by the master discriminating device when the master discriminating device transmits the discriminating task preparation command to the slave discriminating device.

In the present invention, the step of discriminating each phase of the transformer is characterized by discriminating each phase of the electrical equipment when a value obtained by quadrupling the standard deviation is smaller than a value obtained by multiplying the number of taps and the voltage per voltage.

In the present invention, the step of discriminating each phase of the transformer may include calculating a value obtained by subtracting a value obtained by multiplying a tap adjusting number of times and a voltage magnitude per tap from an average value of voltages after tap adjustment for each phase of the transformer, And the standard deviation, and discriminates each phase of the electrical equipment according to the discrimination result.

According to another aspect of the present invention, there is provided a power system phase discrimination apparatus including a transformer for transmitting a tap adjustment command for voltage adjustment to a transformer, Device; And calculating an average value of the voltages for each phase before adjusting the taps of the transformer and calculating an average value of the measured voltages by measuring the voltage after the taps of the transformer are adjusted through the remote control device, And a manual discrimination device for comparing each of the average values before and after the tap adjustment and discriminating each phase of the electric equipment according to the comparison result.

In the present invention, the manual discrimination device may include: a measuring unit for measuring voltages before and after adjustment of the tabs provided in the transformer; Calculating an average value and a standard deviation of the voltage before and after the tap adjustment measured by the measurement unit and generating phase matching information that determines each phase of the electric equipment using the average value and the standard deviation of the voltage before and after the tap adjustment A comparison operation unit; A storage unit for storing the voltage measured by the measuring unit, the average value and the standard deviation of the comparison operation unit, and storing the phase matching information according to the result of the phase determination; And a control unit that performs time synchronization with the remote control device through the communication device and measures the voltage before and after the tap adjustment by the measurement unit, then discriminates each phase of the electrical equipment through the comparison operation unit, And a controller for storing the image matching information generated by the image matching unit in the storage device.

In the present invention, the comparison operation unit may measure a plurality of voltages at predetermined measurement time intervals during a pre-set buffering time before the tap operation, calculate an average value and a standard deviation of the measured voltage, And when the voltage is smaller than a value obtained by multiplying the voltage by the voltage per tap, each phase of the electrical equipment is distinguished.

In the present invention, the comparison operation unit may be configured such that a value obtained by subtracting a value obtained by multiplying a tap adjustment number and a voltage magnitude per tab from an average value of voltages after tap adjustment for each phase of the transformer, And determining each phase of the electrical equipment according to the determination result.

According to another aspect of the present invention, there is provided a power system phase determination method comprising: performing a tap adjustment for voltage adjustment at a predetermined time; And when the taps are adjusted by the transformer, the slave discrimination device measures an average value and a standard deviation of the voltage after the tap adjustment of the transformer, and calculates an average value and a standard deviation of the electric equipments And determining the phase of the image.

In the present invention, the step of discriminating each phase of the electrical equipment is characterized by discriminating each phase of the electrical equipment when a value obtained by quadrupling the standard deviation is smaller than a value obtained by multiplying the number of taps and the voltage per tap.

In the present invention, the step of discriminating each phase of the electric equipment includes a step of comparing a value obtained by subtracting a value obtained by multiplying a tap adjusting number of times and a voltage magnitude per tap from an average value of voltages after tap adjustment for each phase of the transformer, Determining whether each of the phases of the electrical equipment is included in the range of the condition set through the standard deviation, and discriminating each phase of the electrical equipment according to the determination result.

The present invention adjusts the voltage tap of the transformer to measure the voltage of each phase, then compares the voltage before the voltage tap adjustment with the voltage after the adjustment and correctly discriminates the phase of the power system according to the comparison result.

The present invention accurately identifies each phase of the electrical system in the power system at low cost and ensures the integrity of the phase match during power system operation at all times.

The present invention makes it possible to easily discriminate the phases of the electrical equipment in the power system so as to easily perform the load management on the basis of it, and to optimize the management of the transformer according to the phase and to manage the optimum voltage of the high voltage distribution line.

The present invention makes it possible to easily perform load management and line management even when there is a large single-phase load distribution such as a rural road with a long-distance distribution line.

FIG. 1 is a view illustrating a voltage-voltage measurement concept based on transformer tap adjustment according to a first embodiment of the present invention.
Fig. 2 is a diagram showing voltage measurement data of the sensor and the MOF of Fig. 1. Fig.
3 is a view illustrating an installation of a power system phase discrimination apparatus according to a first embodiment of the present invention.
4 is a block diagram of a power system phase discrimination apparatus according to the first embodiment of the present invention.
5 is a block diagram of a transformer having a voltage adjusting tab according to a first embodiment of the present invention.
6 is a view illustrating an example of a combination of a transformer having a voltage adjusting tab and a master discriminating apparatus according to the first embodiment of the present invention.
7 is a flowchart of a power system phase determination method based on a phase discrimination request according to the first embodiment of the present invention.
FIG. 8 is a flowchart of a method of determining a power system phase when adjusting a voltage tap according to the first embodiment of the present invention.
9 is a diagram illustrating a voltage measurement and calculation method for a phase discriminator according to the first embodiment of the present invention.
FIG. 10 is a flowchart illustrating a procedure for discrimination by tap adjustment according to the first embodiment of the present invention.
11 is a diagram showing daily load curves and voltage distributions in a power system.
FIG. 12 is a conceptual view of actual operation of each phase by transformer tap adjustment according to the first embodiment of the present invention.
Fig. 13 is a diagram showing measured voltage fluctuation data by the transformer tap adjustment of Fig. 12; Fig.
14 is a view showing an application example according to a phase by transformer tap adjustment according to the first embodiment of the present invention.
FIG. 15 is a graph showing a voltage measurement result of each measurement position in FIG.
16 is a block diagram of a power system phase discrimination apparatus according to a second embodiment of the present invention.
17 is a view showing a phase matching screen according to the second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a power system phase discrimination apparatus and method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. Further, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the user, the intention or custom of the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

FIG. 1 is a view showing the concept of phase voltage measurement based on transformer tap adjustment according to the first embodiment of the present invention, and FIG. 2 is a diagram showing voltage measurement data of the sensor and MOF of FIG.

In the power system phase discrimination apparatus according to the first embodiment of the present invention, if the voltage adjustment tabs (not shown) of the transformer 10 are adjusted by setting a sufficient time difference for each phase, the effective value voltage of each phase changes over the above- Check the time at which the voltage fluctuation occurred to distinguish the phases. Accordingly, since the power system phase discrimination apparatus according to the first embodiment of the present invention can discriminate only the magnitude of the effective voltage varying from a few seconds to several minutes, it is possible to discriminate an image at a low cost for a large number of power facilities and meters of the power distribution system .

Referring to FIG. 1, a voltage adjusting tap of a transformer winding is used to measure a voltage on a distribution line capable of adjusting the voltage of each phase (A phase, B phase, C phase, or R phase, S phase, T phase) Sensor and MOF (Metering Outfit) were installed and the voltage was measured. Each of the Sensor-R, Sensor-S and Sensor-T corresponds to the A-phase, B-phase, and C-phase of the transformer 10 (see FIG. 3), and MOF-X, MOF- (See FIG. 3) or a load.

The A phase boosts the voltage by raising the winding taps of the A phase transformer 10 at time T1 and the B phase boosts the voltage by raising the winding taps of the B phase transformer 10 at T2 time and the C phase is transformed to the C phase transformer 10) to increase the voltage. For example, when the voltage of about three taps (about 1.9%) is increased and measured at intervals of about 3 seconds, the measured data is as shown in FIG. As a result, it was found that the sensor-R, the MOF-Z, the sensor-S, the MOF-Y and the sensor-T match with the MOF-X. As a result, the MOF- MOF-X can be identified as C-phase.

It is possible to periodically check the phase matching integrity of all the electric equipment 30 requiring phase discrimination by periodically selecting the appropriate time zone by analyzing the daily load curve to increase the discrimination power on the phase and periodically adjusting the tap at the predetermined time, .

The present embodiment is economical because it is intuitive and clear and does not require expensive parts or high-performance processors required for the discrimination. Also, due to the characteristics of the power system, all the systems are hierarchically configured through the transformer 10, so that they can be applied to any system.

3 is a view illustrating an installation of a power system phase discrimination apparatus according to a first embodiment of the present invention.

Referring to FIG. 3, the power system phase discrimination apparatus according to the first embodiment of the present invention includes a master discrimination apparatus (not shown) installed inside or outside a transformer 10 having a voltage adjusting tab (not shown) And a slave discriminating device 40 installed inside or outside the electric equipment (meter, inverter, voltage sensor, etc.) 30 in which the microprocessor is embedded.

The master discrimination device 20 and the slave discrimination device 40 are connected by various communication methods so as to exchange data with each other and the transformer 10 and the electric equipment 30 are connected by power lines of three phases. As the communication method between the master discrimination device 20 and the slave discrimination device 40, a wired or wireless, a wired / wireless hybrid method, or a power line communication method may be employed.

4 is a block diagram of a power system phase discrimination apparatus according to the first embodiment of the present invention.

Referring to FIG. 4, in the first embodiment of the present invention, the master discrimination apparatus 20 and the slave discrimination apparatus 40 may have the same structure.

For the sake of convenience, in the present embodiment, the master discrimination device 20 and the slave discrimination device 40 are distinguished from each other and given different reference numerals. However, the master determination device 20 and the slave determination device 40 may have the same structure, and each of them can operate as a master or a slave depending on the connection method in the system, and so on.

For example, the general electrical equipment 30 may operate as a slave, and the transformer 10 with the voltage adjustment tab may operate as a slave when performing a phase matching operation with an upper voltage regulation tap transformer (not shown) Conversely, it can operate as a master when performing a coincidence operation with a lower electrical equipment 30. [

The master discrimination device 20 and the slave discrimination device 40 may each have a dedicated input / output device, but it is also possible to use an input / output device (not shown) already possessed by the electric device 30 .

The master determination device 20 includes a control unit 26, a communication unit 22, a measurement unit 25, a comparison calculation unit 24, a storage device 23, and an input / output device 21. For reference, the slave discriminating apparatus 20 also has the same components as the master discriminating apparatus 20, and in this embodiment, the master discriminating apparatus 20 will be described as an example.

The communication unit 22 transmits and receives various data to and from the lower slave discrimination apparatus 50.

The measuring section 25 measures the voltage before and after the voltage of each phase is adjusted by the voltage adjusting tab of the transformer 10, respectively.

The comparator 24 calculates an average value and a standard deviation of the voltage of each phase voltage adjusted by the measuring unit 25 and compares the average value and the standard deviation with respect to the voltage before tap adjustment and the voltage after tap adjustment, And the unknown phases of the electric equipment 30 are matched with each other. That is, the comparison operation section 24 compares the voltage before the voltage adjustment tap adjustment and the voltage after the adjustment and discriminates each phase of the electrical equipment as one of the phases of the transformer based on the comparison result.

The storage device 23 stores the voltage measured by the measuring unit 25 and the comparison operation result of the comparison operation unit 24 and also stores the phase matching information according to the result of the phase determination.

The control unit 26 controls the master determination device 20 as a whole.

First, the control unit 26 first determines whether to operate in the master mode or the slave mode. This can be determined through initial user setting, remote setting through the use communication unit 22, and the like.

When operating in the master mode, the control unit 26 receives the tab adjustment plan through the communication unit 22 or receives a phase discrimination request from the lower slave discrimination apparatus 40. In this case, Notifies the discriminating device 40 of the start of work for each top plate, synchronizes the time with the communication ready state, the slave discriminating device 40, and controls the discriminating task. When the phase discrimination operation is completed, the controller 26 stores the phase matching information received from the lower slave discrimination device 40 in the storage device 23.

When operating in the slave mode, the control unit 26 receives phase information and tap operation information from the upper master determination device 20, and synchronizes the time with the master determination device 20, and performs phase-separated tasks. Upon completion of the determination operation, the controller 26 stores the phase matching information in the storage device 23 and transmits the phase matching information to the master determination device 20 as needed.

5 is a block diagram of a transformer having a voltage adjusting tab according to a first embodiment of the present invention.

5, a transformer 10 having a voltage adjusting tap according to a first embodiment of the present invention includes a transformer control unit 14, a transformer measuring unit 12, a voltage tap driving unit 15, a transformer calculating unit 13, And a transformer input / output device (11).

The transformer input / output device 11 sets the parameters necessary for determining the delivery voltage and determining the required number of voltage taps. In general, the dead band width (db) of the output voltage, the equivalent impedance (Zeq) to the load center point, and the load center voltage (Vr_ref) are input.

The transformer measuring unit 12 continuously measures voltage and current of each phase.

The transformer operating unit 13 calculates whether the delivery voltage is in an appropriate voltage range using the measured voltage and current information and parameters. In general, the appropriate range of the delivery voltage should be in the range as shown in Equation 1 below, taking the case of R phase as an example.

Where Vr_ref is the load center voltage, Zeq is the equivalent impedance to the load center point, db is the dead band width of the output voltage, Vr_sending is the delivery voltage, and Ir is the transformer load current.

If the transmission voltage Vr_sending in Equation (1) is not within the proper defined range, the transformer controller 14 determines the necessary number of times of tap adjustment so that the transmission voltage falls within an appropriate range, and transmits it to the voltage tap driver 15.

The voltage tap driving unit 15 adjusts the voltage adjusting tap by the number of taps transmitted from the transformer control unit 14. [ At this time, the transformer control unit 14 monitors the current state for a predetermined delay time so as to check whether the voltage tap adjustment is necessary, in order to prevent an excessive tap operation. In this case, if it is necessary to adjust the voltage even after the delay time has elapsed, the transformer control unit 14 transmits the required number of adjustment taps to the voltage tap driving unit 15 to adjust the tap. This sequence of steps applies equally to phase 3.

6 is a view illustrating an example of a combination of a transformer having a voltage adjusting tab and a master discriminating apparatus according to the first embodiment of the present invention.

6, the master discrimination apparatus 20 according to the first embodiment of the present invention is additionally connected to the transformer control unit 14 of the transformer 10 having the voltage adjustment tab. The transformer control unit 14, And is operated in two operation modes based on the tab adjustment information received from the controller. The first is an operation mode (see FIG. 7) for adjusting the voltage for phase discrimination purposes, and the second is an operation mode (see FIG. 8) actually necessary for adjusting the voltage of the power distribution system.

These operation modes will be described with reference to FIGS. 7 and 8. FIG.

7 is a flowchart of a power system phase determination method based on a phase discrimination request according to the first embodiment of the present invention.

The first operation mode is a case in which the slave discriminator 40 of the lower level requests the discrimination task.

Referring to FIG. 7, first, the slave discrimination device 40 requests the master discrimination device 20 for a discrimination task (S102). The master discrimination device 20 performs communication connection and time synchronization with the slave discrimination device 40, and transmits a discrimination task preparation command to the slave discrimination device 40 (S104).

The slave discrimination device 40 having received the discrimination task preparation command continuously stores the average value and the standard deviation of N (= Td / Ts) data measured at the measurement time interval Ts during the predetermined buffering time Td (S106). For example, if the buffering time (Td) is 1 minute and the measurement time interval (Ts) is 1 second, calculate the arithmetic mean and standard deviation for 60 average voltage values for 1 second. In this case, the final arithmetic mean value (μ1) and the standard deviation (σ1) before the tap change become reference values for comparison. The buffering time Td and the measurement time interval Ts can be suitably determined according to the signal characteristics. When the buffering state is ready, the slave discrimination device 40 notifies the master discrimination device 20 that the phase discrimination preparation is completed (S108).

The master discrimination apparatus 20 requests the transformer control unit 14 to perform tap adjustment for phase discrimination (S110). The transformer controller 14, which has requested the tap adjustment for the phase discrimination, instructs the voltage tap driving unit 15 to perform predetermined phase tap adjustment. When the voltage tap driving unit 15 completes the tap adjustment (S114) and the tap adjustment is completed, the transformer control unit 14 informs the master determination device 20 that the tap adjustment is completed (S116).

Then, the master determination device 20 instructs the slave determination device 40 of the lower slave to start the work for each phase (S118). The slave discrimination device 40 which has received the discrimination device start command carries out phase discrimination operation (S120), stores the phase matching information in the storage device 23 (S122), and then transmits the phase discrimination operation to the master discrimination device 20 (S124). At this time, the slave discrimination device 40 transmits the image matching information together when necessary (S130). The master discrimination apparatus 20 informing the completion of the discrimination operation informs the transformer control unit 14 of completion of the discrimination task (S126). The transformer control unit 14 returns the adjusted tap to the circular state for the phase discrimination if necessary (S128).

FIG. 8 is a flowchart of a method of determining a power system phase when adjusting a voltage tap according to the first embodiment of the present invention.

The second mode of operation may be applied during tap adjustment of a conventional tap transformer 10.

Referring to FIG. 8, if the measured voltage measured by the measuring unit 25 exceeds the specified range and the tap adjustment is necessary (S202), the transformer control unit 14 transmits the tap adjustment plan to the master determination device 20 S204). After receiving the tap adjustment plan, the master determination device 20 confirms the communication connection to the lower slave determination device 40, and synchronizes the time, and then transmits the prepared task by task to the slave determination device 40 (S206).

The slave discrimination device 40 having received the discrimination task preparation command continuously stores the average value and the standard deviation of N (= Td / Ts) data measured at the measurement time interval Ts during the predetermined buffering time Td (S208). For example, if the buffering time is 1 minute and the measurement time interval is 1 second, calculate the arithmetic mean and standard deviation for 60 average voltage values for 1 second. The final arithmetic mean value (μ1) and standard deviation (σ1) before the tap change become reference values for comparison. The buffering time Td and the measurement time interval Ts can be suitably determined according to the signal characteristics. When the buffering state is ready, the slave discrimination device 40 notifies the master discrimination device 20 that the phase discrimination preparation is completed (S210).

On the other hand, the transformer control unit 14 which has transmitted the tap adjustment plan to the phase discrimination apparatus starts the delay time counting. During the delay time, the master discrimination device 20 and the slave discrimination device 40 perform the phase discrimination preparation operation as described above. As described above, if the state requiring the voltage adjustment is maintained even after the delay time is exceeded (S212), the transformer controller 14 instructs the voltage tap driver 15 to adjust the corresponding tap (S214). The transformer controller 14 notifies the master determining device 20 that the tap adjustment has been completed, together with the phase information and the tap adjustment information, in step S216, (S218).

The master determination device 20 transmits the received phase information and tab adjustment information to the slave discrimination device 40 and instructs the lower slave discrimination device 40 to start the discrimination task (S220).

Thus, the slave discrimination device 40 carries out the phase discrimination operation (S222) and stores the phase matching information (S224). In this case, the slave discrimination device 40 transmits the image matching information to the master discrimination device 20 as required (S226).

This mode of operation is used to determine whether the current adjusted phase is correct when the tap is adjusted as needed in the power system. This is to minimize the tap adjustment of the unnecessary transformer 10 for phase discrimination and generally maintain the integrity of the phase coincidence while minimizing the tapping operation by utilizing the operational characteristics that the tab is always operated twice a day There is an advantage that it can be.

Meanwhile, in the above-described process, the average value of each phase voltage is stored before tap adjustment, and the voltage adjustment is made different for each phase, and then the average value is compared to determine phase.

For example, assuming that the voltages on three phases are equal to each other before adjusting the tap, they will have the same average value. For example, assume that the A phase is adjusted by increasing 2 taps, the B phase is maintained as it is, and the C phase is adjusted by 2 taps downward. The phase having a value as large as the two-tap voltage magnitude before the tab adjustment is A-phase and the phase having the value similar to the average voltage value before the tap adjustment is in the B-phase and is lower than the average voltage value before the tap adjustment The phase having the value becomes the C phase. It is effective to carry out tap adjustment of each phase at the same time for faster tap operation and discrimination. However, in the case of performing manually, rather than automatically, as described above, the phase matching operation may be performed by setting a time difference for each phase.

In order to automate the process for each phase, the measurement and phase discrimination method should be normalized. The measurement and phase discrimination method will be described with reference to FIGS. 9 and 10. FIG.

FIG. 9 is a diagram illustrating a voltage measurement and calculation method for a phase discriminator according to a first embodiment of the present invention. FIG. 10 is a flowchart showing a phase discrimination process by tap adjustment according to the first embodiment of the present invention. to be.

In Fig. 9, the comparison operation unit 24 obtains the average (Td / Ts) of voltage data and the standard deviation measured during the Td time before the tap operation. If the voltage distribution follows a normal distribution, about 95% of the data is within ± 2σ, so the voltage after the tap operation must be at least out of this range. That is, the value obtained by multiplying the standard deviation by 4 is smaller than N.times.tap (the number of taps.times.voltage per _tap ) so that the phase of the tap operation can be discriminated clearly. Therefore, Equation (2) below can be used as a conditional requirement.

Here,? Is the standard deviation of (Td / Ts) voltage data measured during Td, N is the minimum number of tap adjustment times required for phase discrimination, and Vtap is the voltage per tap.

The slave discrimination device 40 stores the reference value average in the memory, and when the tap operation is completed, the same number of data is measured in the same manner to calculate an average value. Using the calculated average value, the corresponding phase can be determined by the method shown in FIG.

10, the voltage tap driving unit 15 is driven under the control of the transformer control unit 14 according to the parameter (i) to convert the A-phase tap of the transformer 10 into the Na circuit The B-phase tap is maintained at the Nb circuit current tap, and the C-phase tap is decreased Nc times (S302). At this time, each time the taps are adjusted, the slave discrimination device 40 calculates the standard deviation (?) For these three phases (A phase, B phase, C phase) The absolute value of the smallest number of taps among the three phases is detected (S304).

Next, the slave discrimination device 40 compares the value obtained by multiplying the largest value among the standard deviations [sigma] detected in step 304 by 4 and the value obtained by multiplying the smallest number of taps by the voltage per tap, it is determined whether the value obtained by multiplying the largest value among the maximum value (?) by 4 is smaller than the value obtained by multiplying the smallest number of taps by the voltage per tap (S306).

If the value obtained by multiplying the largest value among the standard deviations by 4 is greater than or equal to the value obtained by multiplying the smallest number of taps by the voltage per tap size, the number of taps is increased (S308) ≪ / RTI >

On the other hand, if it is determined in step 306 that the value obtained by multiplying the largest value of the standard deviations by 4 is less than the value obtained by multiplying the smallest number of taps by the voltage per tap, the slave discriminating device 30 An arithmetic average value and a standard deviation value before and after tap adjustment are calculated (S310 to S314), respectively.

After calculating the arithmetic average value and the standard deviation value before and after tap adjustment as described above, it is determined whether the above-mentioned necessary condition is satisfied (S316, S320, S324). That is, when the voltage distribution having the value obtained by subtracting the value obtained by multiplying the tap adjustment frequency of each phase by the tap voltage value in each phase from the final calculated average value is within the range of ± 2σ of the pre-adjustment arithmetic mean value, (S318, S322, and S326), and ends the phase discrimination (S328).

On the other hand, if the adjustment tab of the transformer 10 is raised or lowered in order to improve the accuracy of the phase discrimination, the change must be easily detectable. The purpose can be easily achieved by increasing the number of adjustment taps of the transformer 10. However, if the adjustment tab is too high, the electrical equipment 30 is exposed to the overvoltage and if the adjustment tab is too low, the under voltage phenomenon may occur and the electrical equipment 30 may fail to operate normally. Therefore, the method of minimizing the number of adjustment taps and finding the voltage adjustment effect should be found. To do this, it is best to adjust the tap at a time when the voltage of the phase in question does not fluctuate significantly.

There are two main reasons for the voltage fluctuation of the power distribution system. The first is the voltage variation of the large transformer 10 in the substation and the second is the variation of the voltage distribution along the distribution line. The main causes of the first voltage fluctuation are the voltage fluctuations of the transmission system and the taps of the transformer (10), and the main cause of the second voltage fluctuation is the load fluctuation. In summary, it is better to select the appropriate time zone for the phase discrimination time when the voltage fluctuation of the power distribution system is small. It is possible to select the time period when the load is constant and the time period when the tap does not change. This is because the load fluctuation eventually leads to tap adjustment. That is, when the load is constant, the tap of the transformer 10 rarely fluctuates. 11 shows the load curve (upper graph) and the terminal voltage of the transformer 10 (lower graph).

11 is a diagram showing daily load curves and voltage distributions in a power system. Referring to FIG. 11, it is a time zone suitable for discriminating an image between 2:00 pm and 4:30 pm. These time zones have different load characteristics from region to region and must be determined according to local characteristics. Calculate the load fluctuation index and the voltage fluctuation index to select the minimum time zone. Referring to FIG. 11, since there is almost no load during the daytime in the rural area, it can be seen that the voltage fluctuation is small and the load is constant in the selected time zone. In selecting the time interval, the standard deviation of the substation draw-out current for each time zone (1 hour interval or several tens of minutes interval) is obtained and used as the load fluctuation index, and the standard deviation of the voltage of the substation bus line is obtained and used as the voltage fluctuation index. Select the time zone where the values of the two indices are minimum as the periodic phase discrimination time zone.

Hereinafter, an actual phase discrimination example according to the tap adjustment of the transformer 10 will be described.

FIG. 12 is a conceptual view of actual phase-by-phase operation by transformer tap adjustment according to the first embodiment of the present invention, and FIG. 13 is a diagram showing measured voltage fluctuation data by the transformer tap adjustment of FIG.

In order to confirm whether the taps of the step voltage regulator (SVR) 10 can be discriminated to determine the phase of the actual field facility, the power supply side # 427 of the transformer 10 (# 438) of the transformer 10 and the taps of the transformer # 430 were adjusted to adjust the voltages of the A-phase and B-phase. When the voltage is adjusted in the transformer # 430, the voltage at # 438 is not influenced at # 427 and the voltage at # 438 is changed.

In order to distinguish three phases, if only two phases are distinguished, the other phase can be determined as the same phase. Therefore, FIG. 13 shows that the voltages of the series 1 and the series 2 are raised by 2 taps to measure the change, and the phase is discriminated, so that all three phases can be distinguished. In case of A, I put 2 tabs at 3:14 PM. I separated 2 tabs immediately, and 2 tabs of B phase voltage were added at 3:15 PM, and I could distinguish that phase, so I dropped 2 tabs. No such change could be found at the voltage of # 427 measured at the same time. As a result, it was found that each phase of the lower electric equipment 30 can be discriminated by appropriately adjusting the tap of the transformer 10.

Because of the characteristics of the instrument installed in the field, the 1-minute average data was obtained, so that it was not possible to observe a sharp voltage change as used with the 3-second average data. The longer the average time of data, the smaller the maximum value of the interval becomes. Therefore, the hardware with the actual discrimination function can easily distinguish the signal change as the average time of data decreases. I tried the actual test with about one second average data, but I was able to distinguish the image easily. That is, Ts is preferably selected to be approximately 1 second or less.

FIG. 14 is a view showing an application example according to a phase by transformer tap adjustment according to the first embodiment of the present invention, and FIG. 15 is a diagram showing a voltage measurement result according to a measurement position in FIG.

Referring to FIG. 14, in order to perform phase matching at a position about 48 km away from a substation, equipments necessary for phase matching with a meter are installed and test method is tested.

As shown in FIG. 15, it is confirmed that the effect of adjusting the tabs from the point where the transformer 10 is installed to the end of the power line is shown. It is possible to discriminate the subordinate electric equipment 30 by phase voltage adjustment of the main transformer 10 of the substation, the SVR of the distribution line, the MV / LV transformer 10, and the transformer 10 of the transformer room have.

FIG. 16 is a block diagram of a power system phase discrimination apparatus according to a second embodiment of the present invention, and FIG. 17 is a diagram illustrating a phase matching screen according to the second embodiment of the present invention.

Referring to FIG. 16, a method of manufacturing and operating the phase discrimination apparatus as a portable system can be used. The second embodiment of the present invention is advantageous in that it is very useful for checking the phase of the required electric equipment 30 and can discriminate an image by utilizing the voltage adjusting tab of the transformer 10 already installed.

16, a manual discriminating device 60 may be employed as the slave discriminating device 40, and the manual discriminating device 60 can be adjusted by a portable remote controlling device 50. [

Therefore, the remote control device 50 transmits various control commands of the user for the phase discrimination, for example, a command for tap adjustment or a command for starting a phase-by-phase operation, via the transformer controller 14 and the manual discrimination device 60 It is possible to perform the same function as that of the master discrimination apparatus 20 by providing the same components as those of the master discrimination apparatus 20, for example, by inputting them to the slave discrimination apparatus 20 or the manual discrimination apparatus 60. The constituent elements of the master discrimination apparatus 20 and their functions are as described above, and a detailed description thereof will be omitted here.

17, the current voltage value is stored in the memory using the snapshot button, and the voltage value measured thereafter is compared with the voltage value stored in the memory The deviation of the stored value can be obtained. In Fig. 17, since the voltage value deviation on the C phase was largest and the tap voltage on the C phase was adjusted, it was possible to correctly identify the phase. According to this embodiment, the phase of the electric equipment 30 can be determined inexpensively and clearly.

The transformer control unit 14 of the transformer 10 controls the voltage tap driving unit 15 at a preset time so that the transformer 10 and the slave discrimination unit 40 can be operated independently Performs tab adjustments.

Accordingly, the slave discrimination device 40 discriminates the phase of the electric equipment 30 like the above embodiment, checks whether or not the phase information currently discriminated by itself is correct and can update it, and if it is new, The unknown image can be confirmed. Here, the manner in which the slave discriminating device 40 discriminates the phase of the electric equipment 40 is the same as that of the above-described embodiment, and thus a detailed description thereof will be omitted here.

There is an advantage that the slave discrimination device 40 periodically discriminates the phase of the electric equipment 40 according to this embodiment.

In this embodiment, the tap of the transformer 10 is adjusted to measure the voltage of each phase, and then the voltage before the voltage tap adjustment is compared with the voltage after the adjustment and the phase of the power system is accurately determined according to the comparison result.

This embodiment accurately identifies each phase of the electrical system in the power system at low cost and ensures integrity of the phase match during power system operation.

This embodiment makes it possible to easily identify the phases of the electric equipment in the power system to easily perform the load management on the basis of them, and to optimize the management of the transformer by phase and to manage the optimum voltage for the different high voltage distribution lines .

This embodiment makes it possible to easily perform the load management and the line management even if there is a large single-phase load distribution like a rural / rural line with a long-distance distribution line.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, I will understand. Accordingly, the true scope of the present invention should be determined by the following claims.

10: Transformer
11: Transformer input / output device
12: Transformer measuring section
13:
14: Transformer control section
15:
20: Master discrimination device
21: Input / output device
22:
23: Storage device
24:
25:
26:
30: Electrical equipment
40: Slave discriminator
50: Remote control device
60: Manual discrimination device

Claims (20)

A master discrimination device for requesting a tap adjustment to a transformer having a voltage adjustment tab to perform tap adjustment of the transformer; And
Calculating an average value of voltages for each phase before adjusting the taps of the transformer, calculating an average value and a standard deviation of the measured voltages by measuring a voltage after the tap is adjusted by the transformer, And a slave discriminating device for discriminating each phase of the electric equipment using the adjusted average value and the standard deviation,
Wherein the master discrimination device performs time synchronization with the slave discrimination device and transmits a phase discrimination task preparation command to the slave discrimination device when the master discrimination device is requested by the slave discrimination device to perform the task discrimination task, Device. delete The apparatus according to claim 1, wherein the slave discriminating apparatus
A measuring unit for measuring voltages before and after adjustment of the tap provided in the transformer;
Calculating an average value and a standard deviation of the voltage before and after the tap adjustment measured by the measurement unit and generating phase matching information that determines each phase of the electric equipment using the average value and the standard deviation of the voltage before and after the tap adjustment A comparison operation unit;
A storage unit for storing the voltage measured by the measuring unit, the average value and the standard deviation of the comparison operation unit, and storing the phase matching information according to the result of the phase determination; And
And a control unit for performing a time synchronization with the master determination device through the communication device and measuring the voltage before and after the tap adjustment by the measurement unit and then determining each phase of the electric equipment through the comparison operation unit, And storing the phase matching information generated by the phase matching information generating means in the storage device. The apparatus of claim 3, wherein the comparison operation unit measures a plurality of voltages at predetermined measurement time intervals during a predetermined buffering time before tap adjustment, calculates an average value and a standard deviation of the measured voltages, And the phase of the transformer is discriminated when the number of taps is smaller than a value obtained by multiplying the number of taps by the voltage per size of the taps. 5. The apparatus of claim 4, wherein the comparison operation unit
Whether or not a value obtained by subtracting a value obtained by multiplying the number of times of tap adjustment by the number of times of tap adjustment and the voltage magnitude per tap from the average value of voltages after tap adjustment for each phase of the transformer is included in a range of conditions set through voltage and standard deviation before tap adjustment for each phase of the transformer And discriminates each phase of the transformer according to a result of the discrimination. The slave discrimination device measures a plurality of voltages at predetermined measurement time intervals during a predetermined buffering time, calculates an average value and a standard deviation of the measured voltages, and then notifies the master discrimination device that preparation for each phase is completed;
When the slave discrimination device is ready for phase determination, the master discrimination device requests a tap adjustment for voltage adjustment to the transformer;
Performing a tap adjustment for voltage adjustment according to a tap adjustment request of the master determination device;
When the tap adjustment is performed by the transformer, the master determination device transmits a command for starting a task by phase to the slave determination device; And
Wherein the slave discriminating device measures the average value and the standard deviation of the voltage after the tap adjustment of the transformer in accordance with the command to start the discriminative operation, and calculates the average value and the standard deviation of the voltage And determining a power system phase determination method. The method according to claim 6, further comprising a step of synchronizing the master identification device with the slave determination device and transmitting a phase-specific task preparation command to the slave determination device. 7. The method of claim 6, wherein the step of determining each phase of the electrical equipment
Wherein each phase of the electric equipment is discriminated when the value obtained by multiplying the standard deviation by 4 is smaller than a value obtained by multiplying the number of taps by the voltage per size of the taps. The method of claim 8, wherein the step of determining each phase of the electrical equipment
A value obtained by subtracting a value obtained by multiplying the number of times of tap adjustment by the number of times of tap adjustment and the voltage magnitude per tap from the average value of the voltages after tap adjustment for each phase of the transformer is determined to be within the range of conditions set through voltage and standard deviation before tap adjustment, And determining each phase of the electric equipment according to the determination result. Transmitting a tap adjustment plan to the master determination device when the measured voltage exceeds a specified range;
Transferring a task to be set by task to the slave determination device according to the tap adjustment plan;
The slave discriminating device measures a plurality of voltages at predetermined measurement time intervals during a predetermined buffering time according to the discrimination task preparation command, calculates an average value and a standard deviation of the measured voltages, Communicating that the discrimination preparation is completed;
When the slave discrimination device is ready for phase determination, the master discrimination device requests the transformer to adjust the tap;
Performing a tap adjustment for voltage adjustment according to a tap adjustment request of the master determination device;
When the tap adjustment is performed by the transformer, the master determination device transmits a command for starting a task by phase to the slave determination device; And
Wherein the slave discriminating device measures the average value and the standard deviation of the voltage after the tap adjustment of the transformer in accordance with the command to start the discriminative operation, and calculates the average value and the standard deviation of the voltage And determining a power system phase determination method. The method as claimed in claim 10, wherein the step of the master determination device
And the master determination device performing time synchronization with the slave determination device. 11. The method of claim 10, wherein the step of determining each phase of the electrical equipment
Wherein each phase of the electric equipment is discriminated when the value obtained by multiplying the standard deviation by 4 is smaller than a value obtained by multiplying the number of taps by the voltage per size of the taps. 13. The method of claim 12, wherein the step of determining each phase of the electrical equipment
It is determined whether the value obtained by subtracting the value obtained by multiplying the number of times of tap adjustment by the number of times of tap adjustment and the voltage magnitude per tap from the average value of the voltages after tap adjustment for each phase of the transformer is included in the range of the condition set through the average value and standard deviation of the voltage before tap adjustment And discriminating each phase of the electric equipment according to a result of the discrimination. A remote control device for transmitting a tap adjustment command for voltage adjustment to the transformer; And
Calculating an average value of the voltages for each phase before adjusting the taps of the transformer and calculating an average value of the measured voltages by measuring the voltage after the taps of the transformer are adjusted through the remote control device, And a manual discrimination device which compares the average value before and after the adjustment and discriminates each phase of the electric equipment according to the comparison result,
The remote control device transmits a command to start the work by phase to the manual type determination device when the tap adjustment is completed by the transformer,
The manual discriminating apparatus comprises:
A measuring unit for measuring voltages before and after adjustment of the tap provided in the transformer;
Calculating an average value and a standard deviation of the voltage before and after the tap adjustment measured by the measurement unit and generating phase matching information that determines each phase of the electric equipment using the average value and the standard deviation of the voltage before and after the tap adjustment A comparison operation unit;
A storage unit for storing the voltage measured by the measuring unit, the average value and the standard deviation of the comparison operation unit, and storing the phase matching information according to the result of the phase determination; And
And a control unit for performing a time synchronization with the remote control device through the communication device and measuring the voltage before and after the tap adjustment by the measuring unit, And storing the phase matching information generated by the phase matching information generating means in the storage device. delete 15. The method of claim 14, wherein the comparison operation unit measures a plurality of voltages at predetermined measurement time intervals during a predetermined buffering time before the tap operation, calculates an average value and a standard deviation of the measured voltage, And when the number of taps is smaller than a value obtained by multiplying the number of taps by the voltage per taps, discriminates each phase of the electric equipment. 17. The apparatus of claim 16, wherein the comparison operation unit
A value obtained by subtracting a value obtained by multiplying the number of times of tap adjustment by the number of times of tap adjustment and the voltage magnitude per tap from the average value of the voltages after tap adjustment for each phase of the transformer is determined to be within the range of conditions set through voltage and standard deviation before tap adjustment, And the phase of the electric system is determined based on the phase of the electric system. The transformer performing tap adjustment for voltage adjustment at a predetermined time; And
Wherein when the tap adjustment is performed by the transformer, the slave discrimination device measures an average value and a standard deviation of the voltage after tap adjustment of the transformer, and calculates an average value and a standard deviation of the voltage of the transformer, And determining,
The step of determining each phase of the electrical equipment
Wherein each phase of the electric equipment is discriminated when the value obtained by multiplying the standard deviation by 4 is smaller than a value obtained by multiplying the number of taps by the voltage per size of the taps. delete 19. The method of claim 18, wherein the step of determining each phase of the electrical installation
A value obtained by subtracting a value obtained by multiplying the number of times of tap adjustment by the number of times of tap adjustment and the voltage magnitude per tap from the average value of the voltages after tap adjustment for each phase of the transformer is determined to be within the range of conditions set through voltage and standard deviation before tap adjustment, And determining each phase of the electric equipment according to the determination result.

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