JP2003061247A - Device for calculating section load in distribution line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a problem, such as overloading, from arising after operation for recovery from an accident or any like operation is performed even if distributed power supplies are linked with a distribution system. SOLUTION: A device for calculating section load in a distribution line comprises a distribution line current measuring means which measures and records the distribution line current of each distribution line, a distribution system condition grasping means which monitors the state of a distribution line circuit breaker, a section switch, and a linkage switch in a distribution system and grasps the condition of the system, distributed power supply facility information recording means which records information on the distributed power supply facilities linked with the distribution system, a section power reception information recording means which records section power reception information, such as customers present in each section of the distribution system, a distributed power supply output measuring means which measures and records the value of current supplied from the distributed power supplies to the distribution system, and a section load calculating means which calculates the load on each section of the distribution system from values obtained by the distribution line current measuring means and the distributed power supply output measuring means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automated operation of a distribution system, and relates to a section load calculation device for a distribution line when distributed power sources are interconnected.

[0002]

2. Description of the Related Art In conventional distribution system automation operation,
When a power distribution system accident occurs, planning of system change / switch work
At the time of execution, flexible operation is performed using the section load value obtained by proportionally calculating the distribution line current value in each section, and operation to prevent overload etc. after the accident recovery operation or system switching operation. It is common to create a procedure.

On the other hand, distributed power sources such as photovoltaic power generation have become widespread in recent years, and when the distributed power sources are grid-connected, it is necessary to calculate the section load in consideration of the influence thereof. In the conventional distribution system monitoring and control apparatus described above, a general method for calculating a section load is to perform a proportional division calculation of a distribution line current value measured by a distribution line drawing unit, for example, by a ratio of an assumed load for each distribution line section.

FIG. 2 is a distribution system diagram in which distribution type power sources are interconnected, and the operation of the conventional example will be described with reference to this. Although FIG. 2 is for explaining the operation of the embodiment of the present invention, for the time being, a conventional example will be briefly described with reference to FIG. Then, before describing an example of a distribution system in which distributed power sources are interconnected, the reference numerals in FIG. 2 are as follows.

First, CB1 is a circuit breaker for pulling out a distribution line, S1 to S4 are section switches, S5 is an interconnection switch, and S6 is a switch.
Is a switch for distributed power, L1 to L5 are switch slave stations, L6 is a slave station for switch for distributed power (with Ig measurement function), L7 is a slave station for breaker for distribution line drawing, and L8 is a distribution line drawing current measurement. Devices, K0 to K4, indicate sections.

If is a distribution line drawing current (= distribution line current) (A), Ig is a distributed power supply output current (A), I1.
~ I4 is load current (A) in each section, Ig is reverse power flow (A) from distributed power source to each section, Iw is interchange current (A) required from interchange source distribution line, and W1 to W4 are each Set value (A) of received power for section consumers, Wg is set value (A) of maximum output of distributed power supply equipment, Wl is contracted received power (A) of customers having distributed power sources, and W is interconnection source interconnection The reserve capacity (A) of the electric wire is shown.

When an accident occurs in the section K1 of FIG. 2, in the conventional distribution system monitoring and controlling apparatus which does not consider the distributed power source, the distribution line current: I measured before the accident occurs.
Proportional division calculation is performed based on f (A) based on the section consumer power reception power setting values W1 to W4 registered in the "section power reception information".

In this case, the section load current values I2, I3, I4 of the section to be accommodated are obtained, and the total of the total load reserve values W of the other distribution lines connected by the interconnection switch S5 is the total of the section destination load. If it is sufficiently larger than that, the interchange current Iw (A) is supplied to the sound section by turning on S5, and the recovery operation is performed.

[0009]

In the case of the above-mentioned prior art, when the distributed power source output Ig (A) is actually present before the accident by the distributed power source connected to the power distribution system,
The total load current of each section K1 to K4 of the distribution line is (If
+ Ig). Further, since the distributed power source is disconnected at the time of an accident power failure (open S6), the interchange current Iw that must be supplied from the other distribution line side that is the interchange source is
The value is larger than the total of the load currents in the interchange section obtained above. Further, the accommodation reserve force W required for the accommodation source distribution line also has a larger value.

Further, when the load is predicted, the section load is similarly obtained from the distribution line current history information, and the factor that reduces the power demand of the distributed power source or the like is not considered. Therefore, when the distributed power sources are grid-connected, there is a possibility that an appropriate value of the present load or the predicted load may not be obtained when performing the load accommodation calculation.

Further, in order to obtain a highly accurate value including the influence of the distributed power source, it is effective to provide a current measuring means for each section switch and interconnection switch, but this system is effective. It is considered that it is economically difficult to realize because it is necessary to provide a current measuring means for each of the large number of division / connection switches.

The present invention has been made to solve the above problems, and even when a distributed power source is connected to a distribution system, the system is changed during an accident recovery operation, a system switching operation, or a system change. It is an object of the present invention to provide a section load calculation device for a distribution line that can obtain a more accurate section load value so that an inconvenience such as an overload does not occur after execution of an operation when planning.

[0013]

A section load calculating device for a distribution line according to [Claim 1] of the present invention provides a distribution line breaker and a distribution line for a plurality of sections for each distribution line of a plurality of distribution lines. In a distribution system monitoring and control device for monitoring and controlling the distribution system state, which has a classification switch that can be remotely monitored and operated, and a connection switch that can be remotely monitored and can be used to classify the interconnection between distribution lines and power sources. Distributing line current measuring means that measures and records the distribution line current of each distribution line, and monitors the states of distribution line breakers, distribution switches, and interconnection switches of the distribution system to grasp the system status Means, distributed power supply equipment information recording means for recording distributed power supply equipment information connected to the distribution system, and section power reception information recording means for recording section power reception information such as consumers in each section of the distribution system , From the distributed power source to the distribution system A distributed power output measuring means for measuring and recording the value of the supplied current, and a section load calculating means for calculating the load for each section of the distribution line from the values obtained by the distribution line current measuring means and the distributed power output measuring means. Equipped with.

In the distribution line section load calculating apparatus according to [Claim 2] of the present invention, in [Claim 1], the distribution line current measuring means, the distributed power supply output measuring means, and the distributed power supply facility information recording means record. Equipped with section load prediction means for predicting and calculating the maximum demand load for each section of the distribution line based on the stored values.

In a distribution system in which distributed power sources are interconnected,
When accommodating load between multiple distribution lines, when performing an accident recovery operation or system switching operation, the distribution line current value at that point and the distributed power output current value obtained from the distributed power output measurement means In addition, in the case of an accident, the required load current value for each section is calculated in consideration of the state in which the distributed power source is disconnected.

Further, in a future system change operation plan, distribution line current history information recorded by the distribution line current measuring means, distributed power source output history information recorded by the distributed power source output measuring means, section power receiving information and The maximum demand load for each section is predicted and calculated from the distributed power facility information.

[0017]

1 is a block diagram showing an embodiment of a section load calculating apparatus for a distribution line according to the present invention. In FIG. 1, reference numeral 1 is a distribution line current measuring means for measuring and recording distribution line current at a lead-out portion of each distribution line, 2 is a distribution line breaker of a distribution system, a section switch for dividing the distribution line into a plurality of sections, and Distribution system state grasping means for observing the open / closed state of the interconnection switch that divides the interconnection between the distribution line and the power source, and 3 for measuring the current value supplied from the distributed power source to the distribution system. Distributed power output measuring means, 4 is history information of distribution line current measured by distribution line current measuring means, 5 is history information of distributed power output value measured by distributed power output measuring means, and 6 is for each section. Section power reception information recording means for inputting / recording the load required for the section to be set, and 7 for inputting / recording facility information such as the power generation capacity set for each distributed power source and the contracted power of the owning customer Distributed power facility information recording Step, 8 is a section load calculating means for calculating a load for each section of the distribution line from the values obtained by the distribution line current measuring means and the distributed power output measuring means, and 9 is a distribution line current measuring means and a distributed power output measuring means. It is a section load prediction means for predicting and calculating the maximum demand load for each section of the distribution line from the values recorded and stored by the distributed power facility information recording means.

In the present embodiment, in the distribution system diagram of FIG. 2, the Ig detection function of L6 is used to periodically measure and record Ig by the distribution system state grasping means, and the latest recorded Ig is recorded when an accident occurs. The load current for each section is calculated using the data.

In the power distribution system of FIG. 2, when the reverse power flow output Ig from the distributed power source is measured before the occurrence of the accident, the power receiving power setting values W3 and W4 of the intervals K3 and K4 are set by the interval receiving information recording means. Then, Ig is proportionally calculated by this value, and Ig3 and Ig4 are calculated (Ig3 +
Ig4 = Ig).

Next, in calculating the section load current from the distribution line current If obtained from the distribution line current measuring means, for sections K3 and K4, from the received power set values W3 and W4 obtained from the section received power information recording means, By subtracting the previously calculated Ig3 and Ig4, the section electric power received is (W3-I
g3) and (W4-Ig4).

As a result, when the section load currents of the sections K1 to K4 are obtained, the section received power is set to W1, W2, (W3
-Ig3) and (W4-Ig4) are used to perform the proportional division calculation as in the past. Thus, the section load currents I1, I2, I3, I4 supplied from the distribution line current are calculated.

Distribution line accident in the example of FIG. 2 (accident section: K
In 1), when Ig is detected before the accident and the distributed power source is disconnected at the time of the accident, the interchange current Iw from the interchange source distribution line necessary for restoration of the sound power failure section is the section K.
It is the sum of the load currents of 2, K3 and K4, and is calculated from the following equation (1).

[0023]

[Equation 1]         Iw = I2 + I3 + I4 + Ig + Wl (A) ............ (1) However, the section load of K2: I2 (A). Section load of K3: I3 + Ig3 + Wl (A). Section load of K4: I4 + Ig4 (A). Distributed power output Ig: Ig3 + Ig4 (A).

In the section K3, the contracted received power Wl (A) of the distributed power source consumer is disconnected,
Since the state of the distributed power supply when S6 (switch for distributed power supply) is turned on cannot always be specified, the interchange current is secured.

The contents of the above-described calculation are obtained by measuring the currents at the lead-out portions of the respective distribution lines by means of the distribution line current measuring means 1 of FIG. 1, and the distribution line currents measured here are stored in the distribution line current history information 4. To do. The section load predicting section 9 is distributed based on the information obtained from the distribution system state grasping section 2, the distributed power output measuring section 3, the distributed power output history information 5, the section power receiving information recording section 6, and the distributed power facility information recording section 7. A section load prediction value is calculated for each section in consideration of the influence of the power source.

When changing or switching the distribution system of the distribution system of FIG. 2 or when planning future facility expansion, etc., in the conventional distribution system monitoring and control device which does not consider the distributed power source, the distribution line current measuring means measures the distribution system current. Distribution line current: If
(A) is obtained from the section power reception information recording means, and proportional distribution calculation is performed according to each section consumer received power set value: W1 to W4,
Section load is required.

In practice, when the distributed power supply output: Ig (A), which is a reverse flow from the distributed power supply connected to the power distribution system, is detected, it is distributed with the load distribution line current: If of the distribution line. It is covered by the mold power output: Ig, and the conventional calculation method was inaccurate.

However, regarding the section load predicting means in this embodiment, when the output Ig from the distributed power source is measured in the distribution system of FIG. 2, the distributed power source output measuring means measures the distributed power source output. Accumulate historical information and create a load curve for distributed generation. Of course, this load curve includes the case where Ig shows a negative value.

On the other hand, also in the conventional distribution system monitoring and control device, the distribution line current measuring means accumulates history information of distribution line current and creates a load curve. When planning a system change or facility expansion, the required load for each section will be calculated using the load curve of the distribution line current of the target distribution system and the load curve of the distributed power output according to the following procedure.

First, the load curve of the dispersed power source output is obtained by the section load prediction means from the dispersed power source output history information,
Distributed power output I to be applied from the time of system change etc.
The value of g is obtained, and the section load supplied from the distributed power source is obtained from the distribution system state at that time.

In the distribution system of FIG. 2, sections K3, K
The received power setting values W3 and W4 of No. 4 are obtained from the section received information recording means, and Ig is proportionally calculated for each section to obtain Ig3 and Ig4. Next, the load curve is obtained from the distribution line current history information, and the value of the distribution line current If to be applied is obtained from the time when the system is changed.

In the distribution system of FIG. 2, sections K3 and K
4. For 4, regarding the received power setting values W3 and W4 obtained from the section power receiving information recording means, the previously calculated proportional distribution calculation results Ig3 and Ig4 of the distributed power output Ig are subtracted,
Section power received is (W3-Ig3), (W4-Ig3)
4) is assumed.

As a result, when the section load currents of the sections K1 to K4 are obtained, the section received power is set to W1, W2, (W3
-Ig3), (W4-Ig4), the distribution line current If as in the conventional case is proportionally calculated. Thus, the section load currents I1, I2, I3 and I4 are calculated. Therefore, the total load of the distribution line in the distribution line system of FIG. 2 is (If + Ig + W
l).

The load of each section is as follows. K
The section load of 1 is I1 (A), and the section load of K2 is I2
(A), section load of K3 is I3 + Ig3 + Wl (A),
The section load of K4 is I4 + Ig4 (A). In addition, the distribution line current value used in the calculation when planning equipment such as equipment expansion:
If and distributed power supply output: Ig uses the maximum value in the history information.

[0035]

As described above, according to the present invention, even in a distribution system in which distributed power sources are interconnected, it is possible to calculate an accommodating current at the time of restoration from an accident and a required load at the time of system change or facility expansion. At this time, the influence of the distributed power supply is taken into consideration, and the section load value that does not cause overload or the like during system operation can be provided to the distribution system monitoring and control device.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an embodiment of a distribution line section load calculation device according to the present invention.

FIG. 2 is a diagram illustrating a configuration of a power distribution system in an embodiment.

[Explanation of symbols]

1 distribution line current measuring means 2 distribution system state grasping means 3 distributed power output measurement means 4 distribution line current history information 5 distributed power output history information 6 section power reception information recording means 7 distributed power equipment information recording means 8 section load calculation means 9 section Load prediction means CB1 Distribution line breaker S1 to S4 Division switch S5 Interconnection switch S6 Distributed power switch L1 to L5 Switch slave station L6 Distributed power switch slave station (with Ig measurement function) L7 distribution Slave station for wire breaker L8 Distribution line drawing current measuring device K0 to K4 Section If Distribution line drawing current (= distribution line current) (A) Ig Distributed power supply output current (A) I1 to I4 Section load current (A) ) Ig Reverse power flow from distributed power source to each section (A) Iw Necessary interchange current from interchange source distribution line (A) W1 to W4 Received power setting value of each section consumer ( ) Maximum output volume setting value of Wg distributed power generation (A) Wl consumer contracts received power with distributed power (A) W flexibility reserve flexibility based interconnection distribution line (A)

Claims (2)

[Claims] 1. A distribution line breaker for each distribution line of a plurality of distribution lines and a classification switch capable of remote monitoring operation for dividing the distribution line into a plurality of sections, and a distribution system between distribution lines and power sources. In a distribution system monitoring and control device that monitors and controls the condition of the distribution system that has an interconnection switch that can be remotely monitored and operated, the distribution line current measuring means that measures and records the distribution line current of each distribution line and the distribution system Distribution system condition grasping means for observing the state of the wire breaker, division switch and interconnection switch and grasping the system condition, and distributed power facility information record for recording distributed power facility information connected to the distribution system Means, section power receiving information recording means for recording power receiving information of customers in each section of the power distribution system, and distributed power output for measuring and recording the current value supplied from the distributed power source to the power distribution system Measuring means and the distribution line current A section load calculating device for a distribution line, comprising section load calculating means for calculating a load for each section of the distribution line from values obtained by the measuring means and the distributed power output measuring means. 2. The distribution line section load calculating device according to claim 1, based on each value recorded and stored by said distribution line current measuring means, distributed power source output measuring means, and distributed power source facility information recording means. A section load calculation device for a distribution line, comprising section load prediction means for predicting and calculating the maximum demand load for each section of the distribution line.