The substation power monitoring system can provide the necessary real-time operation information, especially the information of the switch and protection behavior (accident alarm information), so that on-duty personnel and system dispatchers can grasp the initiative of safety control and accident handling, and at the same time can improve the operation and management of the power grid. Level, reduce power loss, distribution loss, improve power quality.
one. The specific monitoring object of the system The main monitoring objects of the substation microcomputer monitoring system include the following aspects: The analog quantity collection has the temperature, humidity and access control in the high voltage chamber and the main control room. Transformer 0.4kV side current, 0.4kV bus voltage, segmented current, active power and reactive power, 0.4kV outlet current of each branch, transformer temperature. Backup diesel engine generator set voltage, current, active power, reactive power, oil pressure, oil temperature, water temperature, battery voltage, etc. The switch quantity has light switch, circuit breaker switch, high voltage inlet and outlet switch, main tap changer switch, main transformer Low-voltage master switch, sectional switch, 0.4kV branch outlet switch, diesel generator circuit switch, etc.
two. Altai Solutions
2.1 Hardware Implementation
2.1.1 Front-end IPC This solution uses an industrial PC. The front-end IPC can process data uploaded by each module, run automatic control and facilitate maintenance of I/O data in the database, and realize various (telemetry, remote, remote control) data. The upload is released.
In addition to the functions of data acquisition, data concentration, and various communication protocols, the front-end IPC also has unique distribution automation advanced software. It fully meets the requirements of feeder fault location and fault isolation required for distribution network automation.
Front-end IPC adopts industrial control standard design, high reliability, strong anti-interference, performance far exceeds the system composed of workstations or other desktop computers and workstations, ensuring the normal, stable and long-term reliable operation of the entire system. Support multiple communication ports, each communication port can support a variety of different protocols.
2.1.2 After the temperature, humidity and access control substations of substations are evacuated from each substation, in the event of a fire alarm at the substations, the accidents are often delayed because they cannot be discovered in time, causing the accidents to further expand. In addition, when thieves break into the substation, they will lack effective defenses. For this purpose, a batch of temperature and humidity sensors can be installed in the high-pressure room and the main control room, and active infrared intrusion detectors can be installed in the high-pressure room and the main control room door. When the probe senses high temperature or someone breaks in, it will send an alarm message to the background, and at the same time, switch the camera screen and record the scene at the time.
Use DAM3058F to collect temperature and humidity sensor signals. Can collect 8 sensor signals.
The DAM3011 collects the voltage signal from the active infrared intrusion detector to collect 8 alarm signals.
2.1.3 Transformer transformer 0.4kV side current, 0.4kV busbar voltage, segmented current, active power and reactive power, 0.4kV outlet current of each branch, monitoring the operation of the transformer, can make timely response when an abnormal situation occurs . The selected transformer itself should be equipped with a control and protection device. It has perfect temperature detection and fan control functions. It uses the platinum resistance provided by the transformer itself to obtain the temperature of the transformer coil. If the detected temperature exceeds the set threshold, the fan has not yet started, then it is mandatory. Start the fan. The data in the controller can be transmitted to the monitoring center through the RS485 interface and perform the monitoring of the transformer status.
The transformer side current, bus voltage, segmented current, active power, and reactive power were collected with the DAM3501.
Coil temperature was collected with DAM3043 and fan was started and stopped with DAM3018D.
2.1.4 Motor and Backup Diesel Generator Set Protection
Based on the motor's current, voltage and temperature measurements, it provides comprehensive protection for the motor. With short circuit, start overtime, rotor stall, unbalance, ground fault, load loss, undervoltage overvoltage, temperature protection and so on. By detecting the bus voltage before starting and detecting whether the trip circuit is normal, the reliability of the system is further strengthened.
Backup diesel generator set voltage, current, active power, reactive power, oil pressure, oil temperature, water temperature, battery voltage, etc. Monitor the operation of the transformer, and react in a timely manner when abnormal conditions occur.
The current, voltage and diesel generator set voltage, current, active power, and reactive power are collected with the DAM3501.
The DAM3043 is used to acquire the motor temperature signal.
Use DAM3058 to collect diesel generator oil pressure, oil temperature and water temperature.
2.1.5 Switching quantity monitoring (1) In order to make the industrial television monitoring system still function at night, the light of the substation should have the function of time switch or remote control.
(2) Circuit Breaker: Turns on or off a running or failed circuit.
(3) Main tap changer switch, main transformer low-voltage side master switch, sectional switch, 0.4kV branch outlet switch, diesel generator circuit switch, RS-485 serial communication mode. Remote control can be achieved through the communication / closing, remote reading of the measured value, remote read switch status.
Use the DAM3027D to monitor and control the amount of switching.
System diagram
Data Communication Function The communication between the line monitor and the host within the substation adopts the RS 485 communication bus. The communication distance is up to 1 200 m. The baud rate can be set to 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200.
2.2 Software Implementation
Distribution network automation advanced function software selection configuration software
1) Operation monitoring. There is a dynamic display of the main wiring diagram of the substation electrical system and the related analog and digital information.
2) Accident records and alarms. The engineering example requires that when the voltage and current of the 0.4 kV side of the transformer appear under voltage and over current and the computer alarms beyond a certain value, the fault data will be recorded.
3) Report printing.
4) Tips and records for regular start-up of standby diesel generators.
5) Reserve remote monitoring interface and require the system to be easily expanded and upgraded.
Three conclusions Distributed substation monitoring system equipment is universal, simple maintenance, installation, high reliability, complete functions, user-friendly. Through the use of multiple substations and factories and mines distribution rooms in Hebei, Inner Mongolia, and Beijing, the monitoring system described in this article has received good results. The power monitoring and management has gradually become more automated, integrated, centralized, and intelligent.