JPS62138024A - Line voltage drop compensator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a line voltage drop compensator (LDC) used when voltage is adjusted using a load voltage regulator transformer (LRT) in a power distribution system. ) In particular, the present invention relates to a line voltage drop compensator for measuring line voltage drop in a power distribution system and adjusting the voltage of a transformer with a load voltage regulator based on the line voltage drop.

[Prior art] A line voltage drop compensator is a voltage adjustment system that maintains the voltage that fluctuates due to various causes to a constant value. 2 of the transformer with load voltage regulator instead of keeping it at the value
Voltage at a distant load point that is supplied with power from the next bus via the distribution line (feeder) (load point voltage v90)
In order to maintain a constant voltage, we calculate the voltage drop value that occurs when current passes through the distribution line, and compensate for the line voltage drop of 1 from the voltage of the secondary bus of the transformer with load voltage adjustment device. This is a device 1t that calculates the (subtracted) value. The value obtained by compensating the line voltage drop from the voltage of the secondary bus of the transformer with load voltage adjustment device is the load point voltage, so in order to maintain this value at a constant value, a voltage adjustment relay is used to load the load voltage. Raise and lower the taps of the transformer with voltage regulator.

In conventional line voltage drop compensators, the secondary current value of the transformer is used as the load current. However, in general,
N distribution lines belong to one distribution transformer (one bank), and the transformer secondary current is divided into N distribution lines, and the amount of division varies depending on the load situation. Change. Here, each distribution TL line itself causes a line voltage drop, and the magnitude and distribution of the voltage drop also differ depending on the characteristics of each distribution line.

Therefore, in the conventional method, since the current value of each distribution line is unknown, it is difficult to adjust the voltage while accurately grasping the actual state of line voltage drop.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to reduce the line voltage in each distribution line by adopting the current value of all N distribution lines as the load current instead of the transformer secondary current. It is an object of the present invention to provide a line voltage drop compensation 1'z) device which correctly grasps the drop and performs optimal voltage adjustment for all distribution lines.

[Means for solving the problem] In order to achieve such an object, the present invention measures the line voltage drop in the distribution system, and adjusts the voltage of the transformer with load voltage regulator based on the line voltage drop. In a line voltage drop compensator for adjustment, the currents of N distribution lines belonging to one bank of transformers are individually taken in, and these currents are used as load currents to compensate for the line voltage drop of each of the N distribution lines. Calculate the load point voltage VLn for each load point voltage VL
The present invention is characterized in that a load point voltage V90 common to all distribution lines is calculated by averaging n with a weighting coefficient Wn for each distribution line.

[Function] According to the present invention, the line voltage drop is calculated for each distribution line and the load point voltage for each distribution line is obtained. can be compensated. Moreover, since the weighting calculates the load point voltage V90 common to all distribution lines by averaging, it is possible to avoid adverse effects on the voltage adjustment of other distribution lines due to special load trends. It is possible to carry out focused voltage regulation on distribution lines.

[Example] The present invention will be described in detail below with reference to the drawings.

First, in the present invention, the current values of all N distribution lines are taken into the line voltage drop compensator. On the other hand, the constants required to calculate the line voltage drop when a unit current flows through each distribution line are calculated from the configuration of each distribution line and set in advance through the man-machine interface (setting panel) of the device. put.

Furthermore, the line voltage drop compensator calculates the line voltage drop to the load point of each distribution line from each distribution line current value taken in from all N distribution lines and the above-mentioned constant. Conventionally, the following equation (1) has been used as a method for calculating the voltage drop. Here, if the line voltage drop is ΔV, then ΔVn= fn* Sr+4c Ln* In
(1) Here, 1 outlet: Distributed load factor Sn of the distribution line: Equivalent resistance of the distribution line Ln: Exclusion In up to the load point, load current of the distribution line Next, calculate the load point voltage Vln of each distribution line. .

In other words, if the transformer secondary side bus voltage is l, then Vl
n=V1-AVn
(2) Calculate one load voltage V90 common to all distribution lines from the load point voltage Vln of each distribution line. As a calculation method, each distribution line is multiplied by a weighting coefficient Wn and averaged as shown in equation (3).

W mouth = 0.1.2. ... The weighting coefficient Wn of each distribution line is determined by the user according to the following policy, and is set in advance from the man-machine interface section.

(1) For ordinary power distribution lines, set Wn=1. (2) For power distribution lines that do not require voltage adjustment, set ~Vn=O.

(3) Distribution lines with loads that are considered to have no adverse effect on the voltage regulation of other distribution lines as a whole are assumed to have Wn=O.

(4) Distribution lines where you want to perform voltage adjustment intensively are Wn>1
shall be.

The line voltage drop compensator performs voltage adjustment so that the load voltage V90 calculated in this manner is maintained at the target reference voltage. Such a voltage regulation function may be of conventional form and will not be described in detail here.

Next, an embodiment of the line voltage drop compensator according to the present invention is shown in FIG.

Here, 1 is a transformer with a load voltage regulator;
Load currents In of N distribution lines 2 belonging to one transformer 1 are taken into the line voltage drop compensator through CT3, and the secondary voltage v1 of transformer 1 is taken into the line voltage drop compensator through PT4. The stiff voltage is converted into a digital value by Lua (A/D conversion) through the sample and hold circuit 5 and the multiplexer 6. This digital value is stored in the memory 8.

On the other hand, the user sets the constants of each power distribution line through the man-machine interface 9, and the settings 1α are also stored in the memory 8. Using these values, the arithmetic unit IO calculates the load point voltage V90 according to equations (1) to (3). The voltage adjustment function in the line voltage drop compensator is to connect tap R1 from the output section 11 to the voltage regulator 12 of the transformer with load voltage adjustment device so as to maintain the load point voltage V90 at the reference value.
Issue a command to descend.

[Effects of the Invention] As is clear from the above, according to the present invention, the line voltage drop is calculated for each distribution line and the load point voltage for each distribution line is obtained. It is possible to understand and compensate for line voltage drops. Moreover, since weighting is performed to obtain the common load point voltage V90 of all distribution lines by averaging, it is possible to avoid adverse effects on the voltage adjustment of other distribution TL lines due to special load trends. Focused voltage regulation can be performed on specific distribution lines.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing one embodiment of the present invention. 1...Transformer, 2...Feeder, 3...CT. 4...PT. 5... Sample hold circuit, 6... Multiplexer, 7...-A/D converter, 8... Memory, 9... Man-machine interface, 10... Arithmetic unit, 11... Output Part 12... Voltage regulator.

Claims (1)

[Claims] In a line voltage drop compensator for measuring the line voltage drop in a distribution system and adjusting the voltage of a transformer with a load voltage regulator based on the line voltage drop, N distribution lines belonging to one bank of transformers are Take in the currents individually, use these currents as load currents, calculate the load point voltage VLn for each distribution line from the line voltage drop of each of the N distribution lines, and calculate the load point voltage VLn by a weighting coefficient Wn for each distribution line. By averaging the load point voltage V90 common to all distribution lines
A line voltage drop compensator characterized by calculating.