The application of AM5SE series microcomputer protection measurement and control device in the power supply capacity enhancement transformation of a smelting steel power plant

Renyunye Ankrui Electric Co.
, Ltd.
Jiading, Shanghai 201800 Abstract: A metallurgical steel power plant originally had 6kV two-section busbar, and now added a new section III busbar, through the new busbar from equipment selection, control loop principle design and other aspects of transformation, especially the application of AM5SE series microcomputer protection and control device, set control, protection, measurement, switch collection, communication functions in one, improve the reliability, advanced and automation level
of the equipment 。 Keywords: smelting steel power plant; Microcomputer protection measurement and control device; Reliability; Advancement; Automation0 IntroductionThe second total reduction of a smelting steel power plant has two 6kV busbars, which are responsible for the main power supply tasks of water pump station, steel rolling station, electric furnace and other loads, and the original outlet cabinet adopts traditional relay protection mode, and has an independent DC power supply system and metering system
。 In the capacity increase and transformation of 10000m³/h oxygen production equipment, a 31500kVA transformer and a 6kV bus bar in section III were added to the supporting second total reduction, using Accuray AM5SE series microcomputer protection device, and adding Acrel-2000Z power monitoring system to realize the monitoring and management of power consumption in the entire 10kV substation of the plant and improve the level
of automatic management 。 1 AM5SE series device introduction The AM5SE series microcomputer protection device adopts a processor with a main frequency of 168MHz, 16-bit synchronous sampling A/D, and real-time parallel computing of 48-point sampling per week; Equipped with 512K bytes Flash, (192+4)K bytes Sram, external 4M bytes NorFlash, external 512K bytes Sram, sufficient hardware resources, high
reliability.
The device hardware includes power module, CPU module, opening and exit module, control loop module, analog acquisition, communication module, etc.
with modular design and strong
versatility.
At the same time, the device has a power-on self-test function, which can power on the MCU core clock, ADC chip and peripherals, LCD module, incoming acquisition, relay output, SRAM/FLASH/ferroelectric, Ethernet chip and peripherals, serial communication peripherals, USB communication peripherals and other circuits, if there is an abnormality, the relay exit can be blocked to prevent protection misoperation and send out alarm signals
。 2 Specific application of the new 31500kVA transformer of the smelting power plant has a large capacity, so for the transformer, AM5SE-D2 differential protection device, AM5SE-TB backup protection measurement and control device, the two protection devices are used together to realize the differential protection of the transformer, the overcurrent protection of the high voltage side, and the non-electric protection of the transformer; Use AM5SE-F line protection measurement and control device for line protection, mainly set current quick-break protection, fixed time limit overcurrent protection; The AM5SE-C capacitor protection measurement and control device is used to protect the capacitor, mainly setting current quick-break protection, fixed-time overcurrent protection, undervoltage protection, overvoltage protection, and unbalanced voltage protection; The AM5SE-B bus joint protection and backup self-projection device is used to realize the bus joint backup and self-projection function, and at the same time, the function
of blocking and self-casting is set in the event of a failure of the incoming line or manual opening.
2.
1 Operation loop control principle Although the above models of the AM5SE series are different in function, the operating loop control principle is basically the same
.
Compared with the secondary operation circuit before and after the transformation, the original anti-tripping relay current starting circuit is canceled, because the traditional anti-trip operation circuit generally uses current start, voltage holding to achieve electrical anti-jumping, and it is necessary to select the anti-hopping relay according to the current value of the circuit breaker jump and the closing circuit, which has poor versatility, especially for circuit breakers with small trip closing
currents.
Figure 1 The operation loop control principle after the transformation of the secondary schematic diagram of the control loop is shown in Figure 1, which can adapt to the trip current
of 0.
25~5A circuit breaker 。 According to Figure 1, whether it is local control or remote control, when the circuit fails, when the circuit breaker appears manually closed or protected closing adhesion, the TBJ relay coil is energized, the TBJ normally open contact corresponding to the anti-hopping circuit is closed, the FTJ relay coil is energized, and the FTJ normally closed contact of the closing circuit is disconnected, although there is still a closing signal input at this time, but the closing circuit has been disconnected, so it will not be closed again, so as to effectively prevent the occurrence of circuit breaker jumping phenomenon, similarly, if there is a opening adhesion, The anti-trip relay can also be triggered to realize the function
of preventing the circuit breaker from jumping.
In addition, for this operation loop, the jump holding relay TBJ and the closing relay HBJ are added to ensure that whether it is an instantaneous or constant holding of the opening and closing command, the circuit breaker can effectively open and close, and then release the TBJ relay and HBJ relay
after the circuit breaker completes the opening and closing.
2.
2 Principle of self-investment control loop The original I section and section II busbars of the smelting power plant need to be operated in sections with the original two sections of the busbar, that is, if the I section and section II bus bars are de-energized, the No.
3 line will be put into the No.
3 entry line, and the No.
3 entry line will be operated
with the full section of the busbar.
The original bus-joint self-feeding device in the plant does not have an over-drain pressure locking device, even if the 6kV I section bus trips, the backup self-throwing device still operates
.
If the overcurrent protection action trips, the 6kV II segment bus power supply is put into the faulty busbar, which will cause another impact on the fault point, forming greater damage, and even tripping the 6kV II section bus, and the whole station is out of power
.
In this transformation, the function of blocking and self-casting in the event of a failure of the incoming line or manual opening is installed, so as to ensure the selectivity, sensitivity and reliability
of the bus joint self-projection 。 After this transformation, the original backup self-investment protection function is deactivated, according to the power supply mode of the smelting power plant three into the line and two connections, the corresponding backup self-investment logic is customized on the AM5SE-B, and the following functions are realized according to the input 6kV bus voltage signal, current signal and position signal of each circuit breaker in the 6kV section I, II, and III segments: 1) Under normal circumstances, the No.
1 incoming line and No.
2 incoming line are operated in separate columns, and the bus joint is disconnected, and if the No.
1 incoming line or No.
2 incoming line loses power (no voltage and no current), the corresponding incoming circuit breaker is prepared for self-throwing , Zygomatic Circuit Breaker; If the No.
1 line and the No.
2 line are both de-energized, the self-projection jumps the No.
1 and No.
2 lines, merges the No.
3 line, and finally closes the 2 bus link breakers
.
Figure 2 AM5SE-B opening secondary schematic diagram 2) The opening schematic diagram of AM5SE-B backup self-feeding protection device is shown in Figure 2, in X5.
7 access to the protection trip and manual opening signal of the No.
1 line and the No.
2 line, when the circuit fails, the corresponding protection trip output to the latching self-throwing open, at the same time, the backup self-projection function of the device is blocked and cannot be realized
。 3 6kV power monitoring system is transformed to real-time monitoring of the operation and data collection of the entire distribution room of the smelting power plant, and a set of Acrel-2000Z power monitoring system is configured for the plant, and the data protected by the microcomputer is uploaded to the power monitoring system to realize the power monitoring and management of the 6kV substation and improve the level
of automatic management.
The main functions it can achieve are as follows
.
3.
1 Real-time monitoring can visually display the primary system diagram of the substation, and display the remote measurement, remote signal and alarm signal of each circuit of each voltage level in real time
.
3.
2 Electrical parameter query In the distribution primary diagram, you can directly view the detailed electrical parameters of the circuit, and the interface can also be used in the form of a bar diagram to more intuitively display the three-phase current, three-phase voltage, active power, reactive power, power factor, electric energy, etc
.
3.
3 Curve query In the curve query interface, you can directly view the curves of each electrical parameter, including three-phase current, three-phase voltage, active power, reactive power, power factor, temperature and other curves
.
And count the extreme values, extreme value occurrence time, average value, etc.

within the query range of the curve.
3.
4 Real-time alarm with real-time alarm function, the system can issue alarms for remote signal displacement such as distribution circuit breaker, isolation switch, grounding knife division, and joint action, protection action, accident tripping, etc.
, so as to timely warn
users of abnormal situations.
3.
5 Historical event query can store and manage remote signal displacement, protection actions, accident tripping, and event records such as voltage, current, power, and power factor exceeding limits, which is convenient for users to trace system events and conduct historical traceability, query statistics, and accident analysis
.
You can query and sort
by time, type, and device.
3.
6 User Rights Management In order to ensure the safe and stable operation of the system, the system has set up the user rights management function
.
User rights management prevents unauthorized operations (such as remote operations, database modifications, etc.
).

It can define the login name, password and operation authority of users at different levels to provide reliable security for
system operation, maintenance and management.
3.
7 Online monitoring of power quality can continuously monitor
the power quality and power reliability status within the entire distribution system.
Real-time monitoring of power quality of power supply in total incoming lines and important outlet circuits, including steady-state data monitoring, transient data monitoring and fault recording analysis
.
Real-time monitoring of voltage deviation, frequency deviation, three-phase voltage imbalance, three-phase current imbalance, 2~63rd harmonic voltage, 2~63rd harmonic current, 0.
5~63.
5th harmonic voltage, 0.
5~63.
5th harmonic current, harmonic power, harmonic distortion rate, etc.
in the power supply system, and harmonic analysis
is carried out with histogram.
Monitor voltage fluctuations and flicker, voltage dip/dip, and short-term interruptions of important circuits, record events and fault recordings in real time, and provide data sources
for power quality analysis and governance.
Take corresponding measures in time to improve the reliability of the power distribution system and reduce the occurrence
of power supply accidents caused by harmonics.
3.
8 Remote control can remotely control the equipment within the scope of the entire power distribution system
。 For example, the maintenance personnel of the power distribution system can click the corresponding circuit breaker remote signal point through the main interface of the monitoring system to call up the remote control operation interface, and the corresponding operation commands
in the dispatching system or station can be executed in time.
3.
9 Fault recording can automatically and accurately record the changes of various electrical quantities in the process before and after the fault when the system fails, and through the analysis and comparison of these electrical quantities, it plays an important role
in analyzing and dealing with accidents, judging whether the protection is in correct operation, and improving the safe operation level of the power system.
3.
10 Accident recall can automatically record all real-time steady-state information before and after the accident moment, including switch position, protection action status, remote measurement, etc.
, forming the data basis for
accident analysis.
3.
11 Communication management can manage, control and monitor the real-time data of equipment communication within the scope of the entire power distribution system
.
You can view the communication and data messages of
a device.
It can complete communication and data forwarding with various intelligent electronic devices, including microcomputer protection, power meters, intelligent control, DC screen, analog screen, five-defense system and scheduling
.
3.
12 GPS timing can be integrated and configured with Beidou/GPS timing equipment to synchronize timing of the system host to ensure that the entire system equipment has a unified time reference and provide an accurate time reference
for power system fault analysis.
The topology diagram of the power monitoring system after the transformation of the smelting power plant is shown in
Figure 3.
Figure 3 Power monitoring system topology Figure 4 Conclusion Since the power supply capacity increase transformation project of the smelting steel power plant was put into operation in 2020, the device is currently operating well
.
The modified AM5SE series microcomputer protection and control device has a comprehensive configuration and powerful memory function, which provides a basis for accurate analysis of future accidents and correct problem solving; The newly equipped Acrel-2000Z power monitoring system facilitates the viewing of protection information and fault information management, ensuring the safe and stable production
of the plant.
References[1] Yang Zhengxuan.
Application of MTPR series microcomputer integrated protection device in factory power supply capacity enhancement transformation[J].
Electric World, 2010(11):2.
[2] Accuray user substation integrated automation and operation and maintenance solution.
2021.
November edition Author introduction: Ren Yunye, male, currently works at Accuray Electric Co.
, Ltd.
, the main research direction is the application
of relay protection devices.