1. Introduction

The highly configurable DC system of power plants and substations are generally supported by two DC systems as backup of each other. Besides, the batteries with more than 200AH capacity are configured. And for power plants using large generator sets, the batteries with 3000AH capacity are provided. Meanwhile, battery inspection device, shunt insulation monitoring device, battery discharger and the like are added which improve the degree of automation and reduce the manual maintenance intensity of DC system. The inversion function of DC/DC and DC/AC is added according to the load characteristics. The DC system of power plants and substations is as important as the blood for human for all the switch-on/off operations, microcomputer protection and automatic control relies on DC system. The perfect DC system configuration and advanced and mature technology of Lonl Electric improve the reliability greatly.

FOREPOWER DC system consists of AC input unit, rectification module of high-frequency switch, voltage regulating unit, microcomputer monitoring unit, DC feeder, battery pack, insulation monitoring device, battery inspection device, discharge module and inversion module: 

    

 

·AC380V is input to rectification module of high-frequency switch through “AC unit” and microcomputer monitoring module controls the LEP1-LEPn output DC voltage and current. The charge, equalizing charge and floating charge of battery are carried out according to the pre-set charging curve.

The control loop load is supplied with power by LEP through voltage regulating unit with reduced voltage and under the circumstance that the LEP exits or the AC power supply is cut off, the battery is used as the power supply.

The check of battery capacity and activation are carried out by the discharge module.

Different voltage classes are provided by inversion module which meets the special load requirements.

When there is a failure in DC system (e.g. over voltage or earthing) or a failure in the unit module, the inspection and protection are carried out automatically by microcomputer monitoring module with sound and light alarm and communication ports of four remote technology-based units.

The insulation monitoring of bus and each branch is carried out by insulation monitoring device.

The monitoring of voltage of batteries and battery monomers is carried out by battery inspection device. ·

The power of load can be supplied through interconnection switch by dual charger and dual battery which improves the reliability of system.

2. Applicable scope of FOREPOWER

The power supply system which consists of DC power supply and battery is applicable for industries such as electricity, petrifaction, metallurgy, mines and electrified railway and is the DC power supply unit for power plants and substations (500KV, 330KV, 220KV, 110KV, 35KV, etc.)

·For the HV circuit breaker of substations, switch-on/off of air switch and emergency lighting power supply

·For secondary relay protection of substation, automatic control and signal power

·For HV circuit breaker of power plant, switch-on/off of air switch and emergency lighting power supply

·For secondary relay protection of power plant, automatic control, power supply of signal, instruments and meters and automatic device

3. Environmental conditions for usage of FOREPOWER

·Altitude: <2500m

·Ambient temperature: -10℃--+40℃

·Ambient humidity: <98％

·Installation angle: ≤5°

·Seismic fortification intensity: Class VI

·Installation environment: No conductive dust or severe vibration

·No conductive, explosive dust or corrosive gas

·Good ventilation for indoor use

 

4. Characteristics of FOREPOWER

·Quiet design, noise<50db

·Drawer-type structure, hot plug, online maintenance

·All modular system, simple, intuitive, arbitrary screen grouping

·Open, modular and user-oriented software design

·Standard RS232 and 485 communication interface to achieve the four remote technology-based functions

·SCM control for the monitoring of DC system and the whole process of charge and conversion of equalizing charge and floating charge of battery cells

·Built-in perfect system and module protection for SCM monitoring module 

·More than one high-frequency switch charge module operated in parallel connection; N+1 hot standby; automatic share current

·Full range of modules; noise-free and natural cooling design

·When SCM control module is out of work; high-frequency switch charge module will switched in automatic operation mode; the output value of V and I is the default value

·SCM of INTEL80C196KD is selected for SCM control module; standard interface configuration; LCD display for Chinese characters

·Operating voltage: AC380V±20%; capable of normal operation under unstable power supply

·Manual/ automatic voltage adjusting design is adopted for output terminal; applicable for operation under various circumstances

·Resistance to the interference of common and differential mode, radiated electromagnet and static electricity field

·Protection class: not lower than IP20

·100% imported famous semiconductor components; selected in accordance with strict industry standards to ensure the reliability of products;

·Operational status of single battery cell in batteries is monitored online by microcomputer battery inspection device

·Earthing status of branches is monitored online by microcomputer insulation monitoring device

·Discharge module facilitates the activation of batteries 

·A variety of voltage classes are provided by inversion module to meet the load demand

·Various main wiring modes for 10KV-500KV substations and power plants of each size

· automated features for unattended management

 

5. Technical parameters of FOREPOWER:

System efficiency:	≥94%
Noise:	≤50dB
Voltage stabilization precision:	＜±0.5%
Current stabilization precision:	＜±0.5%
Ripple factor:	＜±0.5%
System:	MTBF＞100,000 hours
AC input voltage:	304V-456V
Output voltage (DC220V):	198V-280V(DC220V) 110V-160V(DC110V)
Imbalance degree of current equalization:	≤±3%
Lightning protection:	Class C and D
AC input frequency:	＜50Hz±10%
Control mode:	Microcomputer, manual control and automatic control
Interface:	RS232, RS485 and electrical independent contact
Dimension of cubicle:	2260×800×600mm

 

6. Functions of FOREPOWER

·DC220V (DC110V) power supply is provided

·DC flash power is provided

·Chinesization Operating system with information-rich interface and simple operation; comprehensive monitoring and management on DC system and modules

·LCD display with functions such as data display, real-time alarm list, parameter setting, history alarm record and conversion of even and floating charge

·The automatic operation of charging curve is set according to default setting: 720h automatic even charging, automatic even charging when the AC is out of power for more than 10mins, limits of charging voltage and current, etc.

·Sound and light alarm for abnormal operation of equipment

·RS232 and RS485 communication interface are configured for supervisory computer’s monitoring and control of DC system

·Electrical independent contact output of system alarm is provided for users

·Phase loss protection for AC lines, lightning surge absorption and dual automatic switching are provided

·Voltage regulating function

·Facilitate the activation of batteries by discharge module

·A variety of voltage classes are provided by inversion module to meet the load demands

·Shunt insulation monitoring of DC system 

·Inspection of single cell of DC system 

·Remote management: bus controlling voltage, bus combining voltage, battery current, bus controlling current, bus voltage to earth

·Remote management: bus controlling over voltage, bus combining over voltage, AC over voltage, earthing alarm, LEP alarm, AC alarm, LTY alarm, ZK or RD alarm and the like

·Remote management: conversion of even and floating charge

·Remote management: even and floating voltage and charge current

 

7. Charging curve of battery cells

The charging for batteries is carried out in accordance with the following charging curve which meets the charging requirements of batteries:

http://www.lonl.cn