JP7293085B2 - SYSTEM SWITCHING DETECTION DEVICE FOR POWER SYSTEM, SOLAR POWER OUTPUT ESTIMATION DEVICE AND METHOD - Google Patents

Description

The present invention relates to an apparatus and method for detecting system switching of an electric power system, and in particular, a system switching detection apparatus for an electric power system that enables system switching to be detected without relying on information of switches installed in the electric power system. , relates to a photovoltaic power generation output estimation apparatus and method.

There is a photovoltaic power generation amount estimation device as a device or system for managing and operating a power system. The photovoltaic power generation estimation device estimates the amount of power generated by the numerous photovoltaic power generation devices installed in the power system based on the relationship between the load characteristics of the power system obtained in advance and the amount of power currently being measured. management and operation of

The main input of the photovoltaic power generation amount estimating apparatus is information on the amount of power detected at various points in the power system, and the information on the amount of power measured in the past is used to estimate the load characteristics of the power system. However, when the power system is switched, it is necessary to set the load characteristics to new load characteristics that reflect the new system configuration. There is

A general technique for detecting switching of the electric power system is to use switch information of the electric power system (here, the switch is referred to as the switch including the circuit breaker). Regarding the method of estimating the load, etc. in consideration of the system switching of the power system, Patent Document 1 describes, "On-line information such as the power flow value measured at each measurement point of the power system and the state of the switch is taken in and the power flow A group detection unit that automatically detects load facilities whose values are related to obtain a load estimation group, and for each load estimation group obtained by this group detection unit, calculates the load value of each load facility that constitutes the load facility. A load estimating device for a power system, characterized by comprising a load estimating unit that

JP-A-2001-177991

In the method of Patent Document 1, a signal related to control of the switch is used as a method of detecting the occurrence of system switching. This method requires the input of switch control signals, so the control system must be modified to output the same signals. In addition, since information indicating the connection relationship of the system is also required, it is necessary to continuously update the facility information to match the actual situation. Furthermore, the system whose connection destination is changed in relation to the opening/closing operation of a certain switch changes according to the states of all the switches hierarchically installed under the switch.

Therefore, in order to determine the system to be switched in relation to the switching operation of the focused switch, it is necessary to recursively follow the connection relationship under the switch from the equipment information, which bloats the system. was the problem.

From the above, in the present invention, a power system switching detection device and a photovoltaic power generation output estimation device for a power system that make it possible to detect system switching without relying on information on switches installed in the power system and to provide a method.

From the above, in the present invention, a system switching detection device in a power system including a photovoltaic power generation device, an input unit for inputting power measured at a measurement point of the power system, A comparison unit that detects switching of the power system by comparing the upstream power measured at the upstream measuring point and the total downstream power measured at multiple downstream measuring points on the downstream side of the power system; A substantially zero judgment unit for judging whether the total downstream active power measured at each point is equal to or less than a predetermined value, and there is a measurement point where the total downstream active power is equal to or less than the predetermined value. When the comparison unit compares the upstream reactive power with the total of a plurality of downstream reactive powers, and when there is no measurement point where the total downstream active power is equal to or less than a predetermined value, the comparison unit compares the upstream active power with the plurality of downstream reactive powers. switching of the power system is detected by comparing the total downstream active power.

Further, the present invention is a photovoltaic power generation amount estimating apparatus that obtains a system switching detection signal from a system switching detection apparatus, and the photovoltaic power generation amount estimating apparatus includes a predetermined load characteristic in the active power-reactive power plane and an input In addition to estimating the amount of photovoltaic power generation from the coordinates on the active power-reactive power plane in the active power and reactive power input via the unit, the system switching detection signal is obtained from the system switching detection device, and the load characteristics are corrected. It is characterized by

Further, the present invention is a photovoltaic power generation estimation method for obtaining a system switching detection signal by a system switching detection method, wherein a predetermined load characteristic in the active power-reactive power plane and the effective power in the input active power and reactive power It is characterized by estimating the amount of photovoltaic power generation from the coordinates on the power-reactive power plane and correcting the load characteristics when system switching is detected.

According to the present invention, the occurrence of system switching can be detected only from the power flow measurement value without using switching information of the switch or information related to the connection relationship of the system. Accuracy of quantity estimation can be ensured.

The figure which shows the example of a system|strain structure assumed by a present Example. The figure explaining the principle of the output estimation method of photovoltaic power generation device PV. The figure which shows that load characteristics are also changed when a connection state is changed, and an error of the electric power generation output estimation of a photovoltaic power generation device occurs. The figure which shows the connection of the connection state x. The figure which shows the connection of the connection state y. The figure which shows an example of the electric power measured in each place of the electric power system of FIG. 4, FIG. FIG. 5 is a diagram showing an example of detection of system switching (switching from connection state x to connection state y) using upstream side measurement values and downstream side measurement values; FIG. 10 is a diagram showing a case in which switching from connection state y to connection state x occurs; The figure which shows the example when system switching determination requires caution. The figure which shows the result of having analyzed the cause of system switching determination requiring attention. The figure which shows the countermeasure for the case where system switching determination needs attention. The block diagram of a present Example.

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

FIG. 1 is a diagram showing an example of a system configuration assumed in this embodiment. As for the main flow of electric power, the electric power generated by the power plant 101 is transmitted to the distribution system 105 via the transmission line 104 and the substations 102 of several voltage classes. Among them, active power P, reactive power Q, and the like are measured at measurement points 103 such as transmission lines and substation delivery points.

In recent years, many photovoltaic power generation devices PV have been installed in the distribution system 105 in addition to loads such as large and small consumers 107 and 106 . However, when a system failure occurs, the photovoltaic power generation system PV is automatically disconnected, so only the loads of the consumers 106 and 107 are connected. Therefore, in this case, if the amount of load (hereinafter referred to as actual load) that is not offset by the power output of the photovoltaic power generation device PV is not accurately grasped, there is a possibility of overload at the time of reclosing. The photovoltaic power generation amount estimating apparatus described above is used to grasp the photovoltaic power generation amount, thereby enabling an accurate grasp of the actual load.

Next, using FIG. 2, the principle of the output estimation method of the photovoltaic power generation device PV assumed to be used this time will be described. In the figure, the horizontal axis represents the active power value P of the power flow, and the vertical axis represents the reactive power value Q (hereafter referred to as the PQ plane).

In the figure, L is the load characteristic, which is the trajectory of the power flow when it is assumed that there is no interconnection of the photovoltaic power generation device PV and there is only the load, and the slope is _al . Here, the intersection point 656 between the load characteristic _L with the slope al and the Q axis is referred to as the Q intercept _Q01 of the load characteristic L hereinafter. Also, if the tidal current measurement value 657 measured at the tidal current measuring point 103 or the like is expressed on the PQ plane, its coordinates are (P _m , Q _m ).

Next, a straight line passing through the coordinates (P _m , Q _m ) on the PQ plane and having a slope a _p corresponding to the power factor of the power output of the photovoltaic power generation device PV is drawn down to the load characteristic L at the point of intersection 672. Let the coordinates be (P _X , Q _X ). At this time, P _X - _{P m} becomes the estimated value Ppv of the power generation output of the photovoltaic power generation device PV. In the method of estimating the power output of the photovoltaic power generation device PV, the slope a _l , the slope a _p , and the Q-intercept Q ₀₁ are used as various constants for estimation.

As described above, FIG. 2 shows the load characteristics in the case where there is a system connection relationship (connection state x).

Next, it is assumed that system switching has occurred and the connection relationship of the system under the power flow measurement point 103 has changed. The connection state of the system after the change is assumed to be a connection state y.

FIG. 3 shows how an error occurs in the power output estimation of the photovoltaic power generation device PV when the load characteristic L1 in the connection state x changes to the load characteristic L2 in the connection state y. In this case, the coordinates of the intersection points 672-1 and 672-2 drawn down to the load _{characteristics} L1 and L2 are (P _X1 , Q _X1 ), (P _X2 , Q _X2 ). In this case, if system switching occurs and it is not possible to sense that the load characteristic has changed from L1 to L2, and the load characteristic L1 before system switching continues to be used, the actual power generation output of the photovoltaic power generation device PV is P In spite of being _pv2 , _Ppv1 is misidentified as the power output of the photovoltaic power generation device PV. Therefore, an estimation error of (Ppv1-Ppv2) is generated. As described above, appropriately detecting the occurrence of system switching and switching the load characteristics are important functions for highly accurate power generation output estimation of the photovoltaic power generation device PV.

4 and 5 are diagrams showing the connection relationship of the power system in connection state x and connection state y, respectively. Here, it is assumed that the systems PL1, PL2, and PL3 are connected via a switch D. In FIG. 4 illustrating the connection state x before switching, the system PL1 and the system PL3 are connected in series by the switch D, and the system PL2 is not connected to this series system. In FIG. 5 illustrating the connection state y after switching, the system PL2 and the system PL3 are connected in series by the switch D, and the system PL1 is not connected to this series system.

In the switch D shown in the figure, the switch group responsible for the function of switching the connection destination of the system PL3 to the system PL1 or the system PL2 is simply collectively represented by a c-contact switch. This indicates that the system PL3 on the downstream side is connected to another system on the upstream side (power supply side) by switching and continues to operate. It means that it is not. 4 and 5, SS1, SS2, and SS3 are substations provided in the systems PL1, PL2, and PL3, and power is supplied from transformers Tr to consumers through respective feeders.

In the case of connection state x in FIG. includes the power flow of system PL2. In case of connection state y in FIG. Power flows for PL2 and system PL3 are included.

Focusing on the upstream measurement point 103-1, the load characteristic seen from the upstream measurement point 103-1 is L1 when the connection state is x. On the other hand, in connection state y, the power flow of system PL3 is reduced, so the load characteristic changes as shown by L2.

In the above description, the generator 101 is shown as 101-1 and 101-2 for each system, but these are for the sake of convenience, and are generally connected to the same system at a higher level. there is

FIG. 6 is a diagram showing an example of power measured at various points in the power system of FIGS. 4 and 5. In FIG. Measured values of power on the grid will be described with reference to FIG. One of the grid power measurements utilized in the present invention is the upstream measured value PU (PU1 for grid PL1, PU2 for grid PL2). For example, at an upstream measuring point 103-1 such as a transmission line sending point, the active power P and the reactive power Q are measured in relatively short cycles such as seconds.

Another one of the measured values of power on the system used in the present invention is the downstream measured value (P _Ak , P _Bk for system PL2 and P _Ck for system PL3). On the downstream side, for example, the integrated value of the active power P is measured in a relatively long cycle such as 30 minutes. The downstream measurement values are comprehensively measured for each substation and all bank units.

Therefore, the measured value on the downstream side includes not only the measured value of the power distribution substation but also the measured value of the power generation output of the extra-high voltage consumer and the extra-high voltage photovoltaic power generation device PV. Therefore, the sum of the downstream measured values and the corresponding upstream measured values are almost the same except for losses and measurement errors. For the sake of simplification, the power generation output measurement values of the extra-high voltage consumer and the extra-high voltage photovoltaic power generation device PV will be omitted below. A specific example of the difference between the upstream measured value and the sum of the corresponding downstream measured values is 1.5%. These are signed sums, not sums of absolute values of losses and measurement errors. Furthermore, since the loss and measurement error vary depending on the power flow value, the nonlinearity of the sensors, temperature characteristics, etc., the error may be calculated in advance from the power flow value and corrected. Also, the error may be corrected as a fixed value, or it may not be corrected at all. This is because if it is about 1.5%, it is difficult to greatly affect the detection of system switching.

Here, using the above comprehensiveness, when the connection state is x, the measured value using the upstream measured value PU1 and the measured value using the downstream measured value P _Ak and the downstream measured value P _Ck are (1) They can be related by an expression. In the formulas below, each measured value may be treated as a 30-minute average value, and in this case, each symbol is indicated with a horizontal bar above it.

Here, in the equation (1), the 30-minute average value of active power P _Ak of the upstream side measured value is 30% of the downstream side measured value (P _Ak for system PL1, P _Bk for system PL2, P _Ck for system PL3). It indicates that the sum of the 30-minute average values of the active power converted from the minute integrated value matches within certain margins Lx1 and Lx2. The margins Lx1 and Lx2 are the difference in loss existing on the route between the upstream measurement point and the downstream measurement point, the measurement error of each measurement system, and the like. The same applies to the upstream measured value PU2.

Furthermore, in the case of the connection state y, the relationship between the upstream side measured value and the downstream side measured value is given by Equation (2). Note that the conversion between the power integrated value (in Wh notation) for 30 minutes and the average power is as shown in Equation (3).

In equations (1) and (2), PU1 is the average value of the active power of the upstream system 1 for a certain period, and P _Ak, P _{Bk, and} P _Ck are the active power of the banks of the substations SS1, SS2, and SS3. The 30-minute integrated value (Wh notation), L _{x1, and} L _x2 are the difference in loss existing on the route between the upstream measurement point and the downstream measurement point, and the measurement of each measurement system when the connection state is x. The errors Ly1 _{and Ly2} are the difference in loss existing on the path between the upstream side measurement point and the downstream side measurement point in the connection state y, and the measurement error of each measurement system. Although the loss varies depending on the conditions, it is much smaller than the other terms, so it is sufficient to use the maximum value of the variation range for the determination described later. Moreover, the loss can also be calculated from the resistance and inductance of the system, the specifications of the transformer, etc., even if it is applied to another system with different conditions.

Next, with reference to FIG. 7, system switching is detected using the relationship between the measurement value using the upstream measurement value PU1 and the measurement value using the downstream measurement value P _Ak and the downstream measurement value P _Ck . Give an example. The connection state x is on the left side of the system switching occurrence timing shown in the figure, and the connection state y is on the right side. Among the plots in the figure, the upstream measurement value PU1 indicated by the dotted line is the left side of the equation (1), and the active power measured at the upstream measurement point 103-1 is adjusted to the measurement cycle on the lower side, for example Averaged over 30 minutes. Similarly, the downstream measured value summation_connection state x assumption indicated by the solid line in FIG. 7 is the right side of the equation (1).

Since the equation (1) corresponds to the connection state x, the two plots match within the aforementioned margin on the left side of the system switching occurrence timing. On the other hand, on the right side of the system switching occurrence timing where the connection state y occurs, a divergence occurs in the plot between the upstream measurement value PU1 (the left side of the equation (1)) and the downstream measurement value sum_connection state x assumption. This is because the downstream measurement value on the right side of equation (1) assumes the connection state x, not the actual connection state y.

From the above, by determining whether the divergence between the total value of the downstream side measurement value and the upstream side measurement value due to the assumed connection relationship (connection state x or connection state y) exceeds the threshold, power flow measurement Occurrence of system switching can be detected from the value alone. Examples of the threshold include 1.5 times and 2 times the aforementioned margin. These multiples with respect to the margin are adjusted according to system conditions while observing the degree of erroneous determination.

FIG. 8 shows a case where switching from connection state y to connection state x occurs. The plots in the figure are similar to those in FIG. 7 and correspond to the left and right sides of equation (1). Therefore, since the connection state x is assumed, there is a divergence between the two types of plots before the system switching (from the connection state y to the connection state x) occurs. On the other hand, after system switching occurs, the two types of plots match within a margin because they match the assumed connection state x. Here the margin was within approximately 2% of the maximum. Note that the margin may include a measurement error in the direction opposite to the loss, so it does not necessarily mean that the actual loss is within 2%.

Next, with reference to FIG. 9, an example of a case where system switching determination requires caution is shown. The two types of plots in the figure are the same as those in FIGS. 7 and 8 described above. That is, it corresponds to the right side and left side of equation (1). Here, the entire range in FIG. 9 corresponds to connection state y. Therefore, there should be a divergence between the two types of plots in the figure. However, as shown in FIG. 9, the two plots do not necessarily diverge over the entire area. For example, in the plots indicated as "places requiring special attention for system switching determination" shown in the figure, both plots are in a fairly close range. Therefore, depending on the setting of the margin for system switching determination, system switching may be erroneously determined.

Therefore, FIG. 10 shows the result of analyzing the cause of the system switching determination requiring caution. When the right side of equation (1) is calculated assuming the connection state x in connection state y, the right side of equation (1) is almost equal to the left side, which means that the right side of equation (1) is almost equal to the right side of equation (2). corresponds to What can be derived from this is the conclusion that the active power of system PL3, to which the connection destination changes upon system switching, is approximately equal to zero. In a grid interconnected with the photovoltaic power generation device PV, the active power may become 0 or negative due to a reverse power flow component due to the power output of the photovoltaic power generation device PV. The systems in FIGS. 7, 8, and 9 are also photovoltaic power generation device interconnection systems.

From this, it can be considered that the power flow value of system PL3 is in the state shown in FIG. In other words, when the power flow of system PL3 is expressed on the PQ plane, its coordinates (P _m3 , Q _m3 ) exist on the reactive power Q axis, and the active power is zero. In this case, system switching detection using reactive power, which will be described later, is applied. Furthermore, in preparation for the case of the state (c), it is also determined whether the estimated power output of the photovoltaic power generation device PV is appropriate. State (C) means that when the power flow of system PL3 is expressed on the PQ plane, its coordinates (P _m3 , Q _m3 ) exist near the origin, and not only the active power but also the reactive power is 0. It is in a state of Incidentally, in a normal state where there is no point requiring attention for system switching determination, the power flow of system 3 is as shown in (a). In the normal state shown in (a), the power flow of system PL3 is often in the fourth quadrant of the PQ plane.

Next, FIG. 11 will be used to show countermeasures against the case where system switching judgment requires caution. In this procedure, in a normal state in which caution is not required for system switching determination, determination using the active power P that enables system switching to be detected with high sensitivity (determination using the relationship of formula (1), etc.) is performed. However, as described above, when the load and the active power P of the photovoltaic power generation device PV are offset by the reverse power flow, and the connection destination of the system that is almost 0 is switched, the upper system may The connection cannot be detected from the change in active power P. Also, it cannot be detected in the same way when the system is separated from its subordinates. Therefore, system switching detection using reactive power Q is used.

In addition, it is conceivable that the system switching detection using the reactive power Q cannot compare the upper system and the lower system integrated calculation value as in the case of the active power P described above. This is because the lower system may not measure the reactive power Q in some cases. Therefore, the time difference of the reactive power Q value of the upstream measurement value PU is used for system switching detection using the reactive power Q. FIG. If the reactive power Q value of the upstream measurement value PU changes discontinuously, it is determined that the system is switched. This is applicable when the reactive power Q value of system PL3 is not zero, as in (b) of FIG. In addition, the determination using the time difference of the reactive power Q value also uses characteristics peculiar to system switching. For example, when the system is switched, the reactive power Q value of the upstream measured value PU1 changes in the opposite direction to the reactive power Q value of the upstream measured value PU1 with the same absolute value. In system switching, disconnection from the connection destination before switching and connection to the connection destination after switching cannot be performed at the same time. is disconnected from its destination. Therefore, the time fluctuation of the reactive power Q value also occurs twice in a certain short period. Therefore, the change in the reactive power Q value in two stages can also be used as a feature of system switching. When the active power P of the lower system to be connected or disconnected is not 0 at system switching, the method using the time difference of the reactive power Q can be applied to the active power P in exactly the same way.

The above processing will be described with reference to the flow of FIG. 11 . First, in processing step S431, a power flow measurement value is obtained. These are the upstream flow measurements PU, the downstream comprehensively measured flow measurements P _Ak , P _Bk , P _Ck (often electrical energy, such as Wh), and so on.

Next, in processing step S432, the power flow measurement values on the downstream side are added up for each block that can be used as a unit for system switching. For example, in FIG. 10, the block that can be used as a system switching unit is the 30-minute interval electric energy P _Ck of the system PL3 under the control of the switch. These are not necessarily limited to substation units, but may include extra-high-voltage consumers, distributed power sources, and the like.

Next, in processing step S433, it is determined whether or not there is a block in which the total value is approximately 0. Nearly 0 means a value that can be regarded as 0 within the aforementioned margin. The margin may be calculated from system specifications or determined by actual measurement, as described above. For example, it is 2% of the maximum value of the tidal current value fluctuation width including the measurement error.

If there is no block that is almost 0, it is preferable to use (1) or the like in processing step S434 and apply a detection method using active power that can detect system switching with relatively high sensitivity. If there is a block that is almost 0, a system switching detection method using reactive power is used in processing step S435. In addition, in preparation for a case where detection cannot be performed even by the detection method using reactive power, determination of system switching using the validity of the power output estimation result of the photovoltaic power generation device PV is also used in processing step S436.

The procedure for judging the validity of the power output estimation result of the photovoltaic power generation device PV is as follows. If the load characteristics are not changed at the time of system switching, the estimated value of the power output of the photovoltaic power generation device PV from the upstream measurement values of both the system to which the lower system is newly connected and the system from which the lower system has been removed. cause an error. Said error generally occurs continuously in the opposite direction (over or under) and often gradually increases. Therefore, when the estimated value of the power output of the photovoltaic power generation device PV produces an unreasonable error, it is determined that system switching has occurred. Determination of an unreasonable error is based on the fact that it is outside the range that can reasonably be taken from the change in the amount of solar radiation over time or the rated value of the photovoltaic power generation device PV. The determination can be made from the history of the change range of the time-series value of the power output of the photovoltaic power generation device PV over the past several days without inputting a specific value of the amount of solar radiation. Cases that are clearly subject to rationality determination include cases where it is estimated that there is PV power output even though it is a time zone before sunset or sunrise, or when the power output of the solar power generation device PV becomes a significantly negative value.

In the above-described embodiment, the case where the number of banks per substation is three has been shown, but the same can be applied to cases other than three. Moreover, it is applicable not only to the photovoltaic power generation device PV but also to a system including wind power and other distributed power sources. The number of substations for each system may not be one. A system in which only a special high-voltage consumer, a photovoltaic power generation device PV, or the like is interconnected may be used.

FIG. 12 is a block diagram of this embodiment. The power flow data input/holding means 251 acquires and stores measured values from system equipment. Specifically, upstream side measured values (active power P, reactive power Q), downstream side measured values (accumulated power consumption in units of 30 minutes or the like), and the like are acquired and held.

The power output or actual load estimation unit 252 of the photovoltaic power generation device PV uses the active power P value and the reactive power Q value, which are the upstream measurement values, to determine the system switching state (connection state x or connection state y, etc.) ), the power generation output or actual load of the photovoltaic power generation device PV is estimated using the method described in FIG.

The system switching detection unit 253 detects system switching using the type and method of the measurement value selected by the measurement value selection unit 254 in the preceding stage. For example, when detection of system switching using active power is selected according to the determination result of the measurement value selection unit 254, using equation (1), etc., the total value of the upstream measurement value and the downstream measurement value matches, etc. System switching is determined based on the above. In addition, when detection of system switching using reactive power is selected according to the determination result of the measurement value selection unit 254, the time change of the reactive power Q value of the upstream measurement value is observed, and the reactive power Q value is discontinuous. System switching is determined on the basis of the case of change to

The measurement value selection unit 254 used for detection always calculates a total value (such as the total value of system PL3) for each block that can be a unit of system switching, and the total value can be regarded as almost 0 within the margin range. Observe whether something exists or not. If there is no value that can be considered to be approximately 0, the subsequent system switching detection unit 253 is instructed to use the active power for system switching detection. If there is a value that can be considered to be approximately 0, the subsequent system switching detection unit 253 is instructed to use reactive power to detect system switching.

The system switching detection device for a power system according to the present invention described above is a "system switching detection device for a power system including a photovoltaic power generation device, which includes an input unit for inputting power measured at a measurement point of the power system. , among the measured power, the upstream power measured at the upstream measurement point of the power system and the total downstream power measured at multiple downstream measurement points on the downstream side of the power system are compared to determine whether the power system can be switched. and a substantially zero determination unit for determining whether the total downstream active power measured at each downstream measuring point is equal to or less than a predetermined value, and the total downstream active power is equal to or less than a predetermined value. When there is a measurement point below the value, the comparison unit compares the upstream reactive power with the total of a plurality of downstream reactive powers, and when there is no measurement point where the total downstream active power is below a predetermined value, The comparison unit compares the upstream active power with the total of a plurality of downstream active powers to detect switching of the power system.

Further, the photovoltaic power generation amount estimating apparatus according to the present invention is "a photovoltaic power generation amount estimating apparatus that obtains a system switching detection signal from a system switching detection device, and has a predetermined load characteristic in the active power-reactive power plane, In addition to estimating the amount of photovoltaic power generation from the coordinates on the active power-reactive power plane in the active power and reactive power input through the input unit, the system switching detection signal is obtained from the system switching detector and the load characteristics are corrected. A photovoltaic power generation amount estimating device characterized by

101: Power plant 102: Substation 103: Measurement point 104: Transmission line 105: Distribution line 106: Large consumer 107: Small consumer PV: Solar power generation device SS: Substation D: Switch 251: Power flow data input/ Holding means 252: Power output of photovoltaic power generation device or actual load estimation unit 253: System switching detection unit 254: Selection unit for measurement value used for detection L: Load characteristics 656: Q-intercept of load characteristics 657: Power flow measurement value a1 : Load power factor (slope of load characteristics)
PPv: output estimate

Claims (8)

A system switching detection device for a power system including a photovoltaic power generation device,
An input unit for inputting the power measured at the measurement point of the power system, the upstream power measured at the upstream measurement point of the power system among the measured power, and the plurality of downstream measurement points downstream of the power system A comparison unit that compares the total measured downstream power to detect switching of the power system, and for each downstream measurement point, determines whether the total downstream active power measured at the measurement point is equal to or less than a predetermined value. and a substantially zero determination unit,
When there is a measurement point where the total downstream active power is equal to or less than a predetermined value, the comparison unit compares the upstream reactive power with the total of a plurality of downstream reactive powers,
When there is no measurement point where the total downstream active power is equal to or less than a predetermined value, the comparing unit compares the upstream active power with the total of a plurality of downstream active powers to detect switching of the power system. A power system switching detection device characterized by: A system switching detection device for a power system according to claim 1,
A power system switching detector, wherein the downstream side measuring point is set in a substation having power system switching equipment. A system switching detection device for a power system according to claim 1 or claim 2,
Of the power obtained at the input unit, at least the downstream power measured at a plurality of downstream measurement points on the downstream side of the power system is the total power amount within a predetermined time. Switching detection device. A system switching detection device for a power system according to any one of claims 1 to 3,
A system switching detection device for a power system, wherein the predetermined value in the substantially zero determination unit is 2% or less of a maximum change width of active power of the power system. A system switching detection device for a power system according to any one of claims 1 to 4,
What is claimed is: 1. A system switching detection device for a power system, characterized in that, when detecting system switching using reactive power, the fact that a discontinuous change in reactive power has occurred twice within a predetermined period of time is used as a criterion for determination. A photovoltaic power generation output estimation device for obtaining a system switching detection signal from the system switching detection device according to any one of claims 1 to 5,
The photovoltaic power generation output estimating device calculates the amount of photovoltaic power generation from a predetermined load characteristic on the active power-reactive power plane and the coordinates on the active power-reactive power plane of the active power and the reactive power input through the input unit. is estimated, and a system switching detection signal is obtained from a system switching detection device to correct the load characteristics. A system switching detection method for a power system including a photovoltaic power generation device,
The power measured at the measurement points of the power system is input, and among the measured power, the upstream power measured at the upstream measurement points of the power system and the downstream power measured at a plurality of downstream measurement points on the downstream side of the power system. The total side power is compared to detect the switching of the power system, and it is determined that the total downstream active power measured at each downstream measurement point is less than or equal to a predetermined value,
When there is a measurement point where the total downstream active power is equal to or less than a predetermined value, comparing the upstream reactive power with the total of a plurality of downstream reactive powers,
When there is no measurement point where the total downstream active power is equal to or less than a predetermined value, switching of the power system is detected by comparing the upstream active power with the total of a plurality of downstream active powers. System switching detection method of system. A photovoltaic power generation output estimation method according to detection of system switching by the system switching detection method according to claim 7,
Predetermined load characteristics on the active power-reactive power plane and coordinates on the active power-reactive power plane of the input active power and reactive power are used to estimate the photovoltaic power generation amount, and when the system switching is detected, the load A photovoltaic output estimation method characterized by correcting characteristics.

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