Design and application of remote prepaid power management system in Nanxingyi Community Business Service Center - Master's thesis - Dissertation

Ren Hua

1 Ankerui Electric Co., Ltd., Jiading, Shanghai 201801, China;

Abstract: This paper introduces the remote prepaid power management system implemented at the Nanxingyi Community Business Service Center. The system utilizes intelligent meters to enable remote control and prepayment for electricity usage. It operates through a local network setup, where data is transmitted via fieldbus to the backend. The Acrel-3200 system facilitates both billing and energy efficiency management of the power distribution circuits.

Keywords: commercial complex; Nanxingyi community commercial service center; floor; water meter; prepaid electric energy meter; Acrel-3200; remote prepaid power management system

0 Overview

The Kunshan Nanxingyi Community Commercial Service Center is located in the Kunshan High-tech Zone, situated west of Shanyu Road and north of Meifeng Road, covering an area of 11,933 square meters with a total construction area of 29,681 square meters.

This project involves implementing a remote prepaid power management system for the Nanxingyi Community Commercial Service Center. According to the requirements of prepaid electricity sales, it's essential to manage power distribution circuits on all floors to ensure that electricity is charged before water is supplied, enabling remote collection and billing for water consumption.

1 System Structure Description

The monitoring system primarily manages charge and energy efficiency for the 0.4kV power distribution system on the floors of the Nanxingyi Community Commercial Service Center. It also tracks and bills for water consumption. The monitoring scope includes 50 DTSY1352-NKC meters across 7 sections, 55 remote water meters divided into 6 buses, and communication between on-site meters and the background system using shielded twisted pair cables and a communication management machine. Data is processed and transferred to the background system, allowing real-time connection between devices and the monitoring host to complete energy and charge management functions.

The system adopts a layered distributed structure, consisting of a station control layer, communication layer, and field layer.

As shown in Figure 1:

Figure (1): Network Topology Diagram

The interval device layer includes multi-function network power meters and pre-paid meters, installed in electrical cabinets corresponding to primary equipment. These devices use RS485 interfaces and MODBUS bus communication for on-site data collection.

The communication layer consists of a communication server, which collects field devices and transmits data to the station control layer for interaction between field and station layers.

The station control layer includes high-performance industrial computers, monitors, UPS power supplies, and printers. The monitoring system runs on the computer, collecting and displaying the status of field devices for user interaction.

The network instruments use RS485 interfaces and MODBUS-RTU protocols. RS485 uses shielded cables, typically two-wire connections, offering simple wiring and a maximum transmission rate of 10Mbps. The interface supports half-duplex communication, allowing one side to send or receive data at a time, with up to 32 devices connected over a distance of 1.2km.

2 Remote Prepaid Power Management Main Functions

The system software is divided into three main blocks: centralized meter reading service, remote prepaid power management, and user query system.

The centralized meter reading service runs continuously, performing remote readings for all meters. The remote prepaid system includes account opening, power selling, remote control, and reporting. The user query system allows shops to access personal information, recharge, and check electricity usage. Mobile users can also access the system via a website for real-time queries and remote control. If conditions allow, users can purchase electricity through UnionPay or other methods.

Main features include:

• Quick configuration and ready-to-use: Meter and communication settings can be imported directly into the system.
• Remote centralized meter reading: Eliminates manual readings, providing accurate data within 3 minutes.
• Support for separate pricing, multi-rate, and tiered pricing: Electricity rates and tiers can be set per meter.
• Remote sales: Centralized financial management, real-time delivery, and prevention of fraud through recharge tracking.
• Data security: Financial-grade 3DES encryption ensures secure data transmission.
• SMS alerts: Three levels of warnings are sent when balances are low or arrears occur.
• Remote control: Enables remote operation of any meter for efficient management.
• Energy analysis and query: Users and admins can check daily energy usage for each meter.
• Mobile phone inquiry: Supports self-service electricity purchases and inquiries via mobile web.

Traditional IC card systems require users to pay first before receiving power, but they often lag in data updates, requiring manual readings and real-time monitoring. With the remote prepaid system, users can avoid manual processes, enabling real-time monitoring, remote recharging, and control, supported by SMS alerts and mobile websites. This enhances efficiency, reduces costs, and improves security against tampering and data leaks.

3 Case Analysis

The Kunshan Nathan City remote prepaid system is divided into two parts: substation and floor distribution boxes for monitoring and charging. The substation handles energy statistics and analysis, while the floor part focuses on prepaid power management and remote operations.

The floor distribution boxes use DTSY1352-NKC smart meters, which measure standard power parameters such as three-phase voltage, current, active power, power factor, frequency, and energy consumption.

Key on-site functions include:

1. Centralized Meter Reading Service: Reads all meters at regular intervals and sends alarm SMS notifications automatically. Requires hardware SMS cats for shop users.

2. Remote Prepaid Power Management System: Divided into five modules—operator login, system configuration, user management, power sales, and report center. Each module supports specific operations like account creation, meter reading, and report generation.

3. Reports and Queries: All reports support Excel export, including sales, energy, and alarm reports.

4. User Interface Features: Includes login management, building group settings, communication manager configuration, and batch operations for meter status, price setting, and data export.

5. Sales and Control: Allows remote electricity sales, power-off, and reconnection, with detailed records and alerts.

6. Energy Analysis and Reporting: Provides daily, monthly, and annual energy consumption reports based on date ranges, locations, and meters.

The system supports multiple meters per household, transfer of old meter balances, and flexible pricing options. It also offers visual alerts and remote control commands such as setting prices, alarms, and forced power cuts.

4 Conclusion

With increasing electricity demand and stricter quality standards, commercial users face challenges like unpaid bills, increasing operational risks for power companies. To improve collections and prevent losses, our company provides a comprehensive prepaid solution. The system enables "pay first, then use" and selectively limits power during shortages or government-driven energy-saving initiatives. By ensuring timely payments, it eases financial pressure on businesses and prevents unauthorized electricity use, enhancing security and efficiency in power management.

Reference Standards:

ISO/IEC11801, GB/50198, GB50052-2009, GB50054-2011, IEC 61587, DL/T448-2000, DL/T 698.1-2009, DL/T 698.2-2010, DL/T 698.31-2010, DL/T/814-2002, DL/T5137-2001, GB2887, GB/T18460.3