JPH10227813A - Automatic meter reading system for electric power - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable automatic collection of measured values of watthour meters dispersively installed by collecting the measured values of the watthour meters dispersively installed in areas through a metal sheath of a high voltage cables. SOLUTION: Measured values of watthour meters M1-M4 installed within areas 2 and 3 are collected per area through communication circuits 5 and 6 utilizing a high voltage cable 4 having a metal sheath between a main substation on the center 1 side and substations in the areas and are modulated into a carrier to be transmitted to the metal sheath of the high voltage cable 4 while the carrier transmitted to the center 1 from the areas 2 and 3 through the metal sheath of the high voltage cable 4 is demodulated to collect the measured values of the watthour meters M1-M2. The measured values of the watthour meters M5-M7 installed in the center 1 are collected through a communication circuit 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic meter reading system for automatically reading meters such as a wattmeter installed in a distributed area.

[0002]

Conventionally, a customer such as a factory with a large contracted power once has a high voltage (6.6 KV,
22KV) is transmitted to the main substations, then transmitted to substations in several areas by high-voltage cables, and converted to lower voltage at each substation for use. Therefore, the measurement of the amount of electric power used is performed by a watt-hour meter installed for each area,
A meter reading method is used in which a meter reader periodically reads and counts. As described above, in the meter reading by the meter reader, if a large number of wattmeters installed in a wide range are to be metered by a limited number of meter readers on the same date and time, a great burden is imposed on the meter reader. In addition, when the watt-hour meter was read visually, recorded in a form or the like, and counted, it was inevitable that misreading and erroneous writing occurred due to carelessness of meter readers. For this reason, there has been a demand on the consumer side to automate meter reading in order to save labor and speed up the processing of meter reading data.

[0003]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention relates to a high-voltage high-voltage power supply having a metal sheath laid between a main substation on the center side and substations in a plurality of areas. Using a cable, the measured values of watt meters installed in each area are collected via a communication line, and the measured values are modulated into a carrier wave and sent to the metal sheath of the high-voltage cable. The carrier wave sent from each area to the center side via the metal sheath is demodulated to collect the weighed value of each wattmeter.

[0004]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an embodiment of the present invention. In the figure, a main substation (not shown) is installed on the center 1 side, and electric power branched from the main substation is transmitted to the areas 2 and 3 via the high-voltage cable 4 and the like. The high-voltage cable 4 is covered with a metal sheath made of copper or the like. By transmitting a carrier wave to the sheath, communication between the areas 2 and 3 and the center 1 is enabled. In the areas 2 and 3, watt-hour meters M1 and M2, watt-hour meters M3 and M4, and the like are installed, respectively.
M4 to M4 are equipped with a pulse transmitting device, and a pulse corresponding to the measured value is output and input to the meter reading terminals T1 to T4, respectively.

The meter reading terminals T1 to T4 are connected to watt hour meters M1 to M
In addition to accumulating the pulse signals from No. 4 and storing them as meter reading values, it has an RS-485 interface and transmits meter reading information to the communication lines 5 and 6 in response to meter reading requests from the meter modems MD1 and MD2. Meter side modem MD
1, MD2 modulates signals input from the communication lines 5 and 6 of the RS-485 standard into carrier waves and sends them to the sheath of the high-voltage cable 4 and demodulates the carrier waves sent from the high-voltage cable 4 for communication. The signals are sent to the terminals T1 to T4 via the lines 5 and 6. Note that a DSM (Demand Site Management) unit is connected to the meter reading terminal T2 in the area 2, and the center 1 controls ON / OFF of a power supply of an AC100V load connected to a relay of the DSM unit.

[0006] The center modem MD3 of the center 1 demodulates the carrier waves transmitted from the areas 2 and 3 via the high voltage cable 4 and sends them to the center device 8 via the RS-232C standard communication line 7. The signal input from the communication line 7 is modulated into a carrier and sent to the sheath of the high-voltage cable 4. On the center 1 side, watt-hour meters M5 to M7 such as a main watt-hour meter are installed.
From M7, a pulse corresponding to the measured value is output and input to the meter reading terminals T5 to T7, respectively. Meter reading terminal T5
T7 accumulates the pulse signals from the watt-hour meters M5 to M7, stores them as meter reading values, has an RS-485 interface, and transmits meter reading information to the communication line 9 in response to a meter reading request from the center terminal T8. Send.

The center device 8 stores the measured values of the watt-hour meters M1 to M4 of the areas 2 and 3 and the measured values of the watt-hour meters M5 to M7 of the center 1 inputted through the communication line 7, and also stores the DSM. An operation signal is transmitted to a device such as a unit. The center device 8 functions as a meter reading data collection processing device, and also performs various forms output of meter reading data, displays graphs, and controls load.

FIG. 2 is a diagram hierarchically showing the relationship of signal transmission in the system configuration of FIG. The area address in the figure is the identification number of the meter-side modem, and the address is the identification number of the meter reading terminal. The specific scale of this system is as shown in Table 1.

[0009]

[Table 1]

[0010] As shown in Table 1, in this system, up to 32 watt-hour meters can be connected to one area, and up to 16 areas can be supported. Up to 512 watt-hour meters can be managed.

The communication specifications between the modems are configured as shown in Table 2.

[0012]

[Table 2]

FIG. 3 is a diagram showing the configuration of a communication frame for transmitting an address and a communication frame for transmitting the number of pulses transmitted and received in the system of FIG. As shown, one frame is composed of 22 bits.

FIG. 4 is a diagram showing the timing of data transmission and reception in the system of FIG. As shown in the figure, it takes a maximum of 670 ms from sending the command by the center device to obtaining the meter reading result.

The system according to the embodiment of the present invention has the following features. (1) Regarding the transmission line, mainly the distribution line transport system and RS-
Since the 485 system is adopted, and the distribution line transport system uses the sheath of the high-voltage cable for the transmission line, there is no need to newly install a transmission line. Further, in the RS-485 system, since devices can be connected in a multi-drop manner, a system can be constructed at low cost. (2) The communication equipment of this system does not include a CPU, and performs communication control with a hardware configuration. Therefore, there is no transmission delay due to software analysis or the like.

(3) Although the transmission speed is 100 bps,
The meter reading terminal is capable of switching between 100 bps and 4800 bps, and 4800 bps when the distribution line transport method is not used.
bps transmission. (4) This system has an automatic meter reading function, and by registering the meter reading date and time in advance, it is possible to automatically perform meter reading for all areas at the designated date and time.

(5) This system is a DSM having a load control function of a power supply installed in each area from the center side.
Unit on / off control can be performed. (6) The present system has a demand function, and issues an alarm when there is a risk of exceeding the set value. (7) As a screen display function of the center device, a list display for grasping meter reading conditions such as a power factor of the watt hour meter, a CT ratio, etc.
High-voltage branching, system diagram and plan view showing the location of equipment installation are enabled. In addition, management information such as ground resistance value and transformer capacity for each area can be displayed.

[0018]

As described above, according to the present invention, the distributed values are collected at the center via the metal sheath of the high-voltage cable, and the measured values of the respective wattmeters installed in the distributed area are collected. It is possible to automatically collect the measured value of the installed watt-hour meter.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram hierarchically showing a relationship of signal transmission in the system configuration of FIG. 1;

FIG. 3 is a diagram showing a configuration of a communication frame transmitted and received in the system of FIG. 1;

FIG. 4 is a diagram showing data transmission / reception timings in the system of FIG. 1;

[Explanation of symbols]

 1 Center 2, 3 Area 4 High voltage cable 5-7 Communication line 8 Center device 9 Communication line M1-M7 Watt hour meter MD1, MD2 Meter side modem MD3 Center side modem T1-T7 Meter reading terminal T8 Center side terminal

Claims (1)

[Claims] 1. A high-voltage cable having a metal sheath and laid between a main substation on the center side and substations in a plurality of areas, and a weighing value of a watt hour meter installed in each area for each area. A weighing data transmitter that collects the data via a communication line, modulates the weighed value into a carrier wave, and sends it out to the metal sheath of the high-voltage cable, and a carrier wave sent from each area to the center side through the metal sheath of the high-voltage cable An automatic meter reading system for electric power, comprising: a measuring value data receiving device that demodulates and collects a measuring value of each watt-hour meter.