I. Engineering Background Huaneng Chongqing Yurong Power Plant has a total installed capacity of 2640MW, which is the largest thermal power plant in the west. Among them, the 3rd and 4th machine assembly machines for the second phase of the project are 2×360MW, which was introduced in France for ALSTOM equipment in 1997. The second-stage boiler was manufactured by STEIN with an evaporation of 1099.3 T/H. The steam turbine is a subcritical, intermediate reheat, triple-cylinder, dual-cylinder, steam-impulse steam turbine manufactured by STG. The second phase of the project DCS uses the distributed control system ALSPAP320 provided by the French company CEGELEC as the unit's main control system and the main monitoring system. The ALSPAP32O includes the main functions of data acquisition DAS, closed-loop control CCS, sequential control SCS, furnace safety system BMS and so on. In addition, the turbine control system adopts the MlCROREC control system provided by the French company GECALSTOMSTG, which realizes the function of the digital electrohydraulic control system of the steam turbine.
In the past ten years since the unit was put into operation, with the upgrading of some local equipment, the unit control system was in urgent need of upgrading and capacity expansion, but the P320 system could not meet the need for open upgrade and expansion of the unit due to the lack of scalability. Coupled with the P320 system control card aging serious, spare parts purchase difficulties and a series of reasons. In order to facilitate the unified management of the whole plant, ensure the safety of the unit, and reduce the burden on the operation and maintenance of personnel, it was decided to reconstruct the DCS in the second phase.
Second, the system outline Second phase of DCS transformation selected the United States Westinghouse's OVATION control system. Its biggest feature is that OVATION adopts true open computer technology. Data networks are connected in a redundant manner. Redundant configurations such as controllers and power supplies are used to control the failure of any component in the system, without affecting the entire system. System work. OVATION has a rich set of algorithms and application software. It uses related database technology and Powertools tools that are in line with today's popular software design to make configuration more convenient. It is easy to configure, easy to expand, and easy to use. OVATION also provides comprehensive data monitoring functions, as well as historical data, data trend information, human-machine interface is more friendly, and can provide the unit with the best operating control environment to ensure that the unit operates in the best condition.
OVAT10N concentrates on DAS, SCS, FSSS, MCS, ECS, DEH, ETS, MEH and other functions. The control of the two unit units is realized by two sets of DCS respectively. The public system (circulation pump room, fuel pump room, air compressor, public The power supply system, network control system, etc. are controlled by the DCS public system (in which the remote I/O cabinets are also installed in the circulating pump room, network control building and fuel pump room fuel delivery system respectively), and the DCS public systems are connected separately. Into the DCS network of two unit units.
Unit unit system includes 12 workstations, namely 7 operator stations (including 1 large-screen operation station), 1 server/engineering station, 1 history station, 1 OPC server, 1 SIS communication management station, including 18 controller cabinets, H extension cabinets, 1 relay cabinet, 1 MFT trip cabinet, 2 power cabinets, 1 switch cabinet, and 5 reserved cabinets.
The public system includes: 1 electrical operator station, 3 controller cabinets, 2 expansion cabinets, 2 remote cabinets, 2 power cabinets, and 1 switch cabinet.
Apart from the steam drum water level CRT and the furnace flame CRT, the unit unit only has a small amount of conventional digital display meter and light card, and two large screens at the same time. As a back-up operation, the operator's station and the vertical plate still retains the boiler MFT, the turbine opening, the small engine tripping, the generator group emergency trip, and the important oil pump hard start button.
Third, the characteristics of the OCS system transformation 3.1 Power supply and grounding system UPS220VAC power from the electricity into the DCS's two power distribution cabinets, and then by the A, B power cabinets to allocate all the way to the same power controller cabinet, to achieve power redundancy Configuration. Each controller cabinet power module has a protection alarm function. The 24VDC output from the power module is used for the loop circuit of the analog loop power supply and the output relay, and the output 48VDC is used for the query voltage of the switching loop signal. In addition, according to the characteristics of the field devices, the external 48VDC supplied from the electric DC room is connected to the corresponding busbars of the cabinets, and the external 48VDC power supply is connected to the air switches corresponding to each output DOC card in parallel by the busbars. The line directly drives the field circuit. In this way, the isolation of the drive power between the DOC cards is realized, and the accidental wave caused by the single loop trip is reduced. Taking into account the actual operation of the equipment, the electromagnetic valve of the deaerator, the water supply and the furnace pump accident cooling valve three solenoid valve drive circuit, and the external supply 48VDC separate air-distribution output. Each externally supplied 48VDC busbar circuit and each digital output DOC card open circuit are designed with monitoring relays and auxiliary contacts to provide the corresponding 48VDC power supply signals.
According to the system requirements, the single point to ground resistance of the cabinet is less than 1Ω. The set of DCS systems has only one unified common ground, namely electrical ground. Electrically distinguishable are DCCOM and ACCOM, ie DC and AC grounds. ACCOM is used for the shielding of external weak signals, such as thermocouples, thermal resistance, current signals, etc. ACCOM provides a low-impedance discharge channel for fault currents and high-frequency noise, making the device housing and the ground at the same potential. The DCCOM is used as a common ground negative terminal for the 48VDC, 24VDC DC power supply. It establishes a zero potential reference point for the system's digital process control, and it can also effectively eliminate high frequency noise. In fact, DCCOM and ACCOM have interconnected in the DCS controller cabinet. In the system controller cabinets and expansion cabinets, DCCOM is interconnected by star connection. This method of connection can avoid system-wide defects caused by the disconnection of a certain link in the middle of the connection; and ACCOM is only used as Shielding ground, so its connection is designed to be connected to the interconnection between the disk.
3.2 TSI system transformation TSI system originally selected the United States BENTLY company complete sets of products. According to the design requirements, the Phillips MMS6000 system is now uniformly selected. At the same time, the cabinet card and on-site TSI measurement probes are to be modified and replaced.
3.2.1 The rotational speed measuring device, originally a three-speed-speed generator, is now to be removed and replaced. Uniformly replaced with 8 reluctance speed probes PR9376, of which 3 speed probes are used for TSJ overspeed protection, 3 probes are used for DEH speed reference signal, 1 probe is used for zero speed start and stop disc brakes, 1 probe is used In the head tachometer display.
3.2.2 The axial displacement device was originally a single eddy current probe measurement. In order to ensure the safety of the unit, it is replaced by three eddy current probes. The signal of the probe is PR6423. After the three measurement channels process the on-site signal, they are connected through a hard circuit with 3 options and 2 logic connections. The output hard contacts directly interrupt the turbine.
3.2.3 In the original TSI system, only the Y direction bearing is vibrated by the axis vibration signal. In this modification, X-axis vibration probes have been newly installed in the field. The probe model is PR6423, and the analog output value can be sent directly to the DAS system for display and analysis alarms. In this way, on-line monitoring of shaft vibration and wave vibration in the XY direction can be realized for any turbine bearing shell, which satisfies the need for full-frequency analysis of the unit.
3.2.4 According to the reconstruction plan, other differential expansion probes (3 sets), key phase probes (1 set), vibration probes (16 sets), and eccentric probes (1 set) were all replaced. The on-site transfer terminal box, probe mounting bracket, and probe displacement conversion device were also partially replaced, and some of the speed cables were re-placed.
3.3 DEH system The DEH system of the second stage of the Sulfo-power plant includes a series of functions such as OPC, BTC, ATC, TSI, ETS, and VMDS. The main steam turbine control system before the transformation consists of the following components:
3.3.1GSEOOIAR cabinet is the steam security cabinet, including ETS, adjustable door activity experiments and other functions.
3.3.2 GMA00lAR cabinet is a body measuring cabinet containing the temperature and pressure detection points of the turbine body.
3.3.3 GREO01lAR, GRE002AR, GRE003AR Cabinets, AGC, Door-to-door Control, Unit-uploading, and other functions. In this DCS transformation, the AGC function has already been moved to the MCS, and the rest of the system is ready to be removed and incorporated into the new DEH. The control function of the original DEH control Ml-CROREC is now realized by the OVATION control system.
However, in the actual simulation adjustment experiment process, due to the electro-hydraulic servo drive card provided by OVATION company, the maximum output of the regulating valve electric/hydraulic drive current can only reach about ±40mA, while the original AL-STOM company's complete set of supporting high and medium turbines The control driving current of the pressure regulating valve needs to be about ±600mA, and the servo cards supplied by OVATION cannot output such high electric/hydraulic servo drive current. This consideration was added to the mid-level driver amplification in the new DEH, and it was considered that the system security was unstable and only abandoned. The final connection scheme is to retain the original RBP2 door positioning control cabinet, ie, the mechanical measurement system and valve position system in the electro-hydraulic control system are retained. Instead, DCS provides standard current drive control signals that are hard-wired to RBP2, and then the original RBP2 system is responsible for proportional amplification, and then used for output to drive the turbine high and low pressure regulators.
Some of the original DEH's important pressure measurement transmitters are designed as single measurements. According to the requirements of the transformation, they are now uniformly added to three measurements. The main parameters added are condenser vacuum, turbine lubricant pressure, high pressure cylinder exhaust pressure, first stage steam pressure of the high pressure cylinder, steam pressure before the steam turbine main valve, inlet pressure of the lower part of the medium pressure cylinder, etc. The three measurement points are output by the logic 3, 2 and comparison to ensure the reliability of the important parameter measurement.
The ETS system is directly incorporated into the DEH instead of a separate PLC-type ETS. The logic function of the ETS is realized by the DEH, and the configuration of the main protection function of the turbine is intuitive and concise. The solenoid valve circuit in the disk is powered by two independent 24VDC power conversion modules. The solenoid valve is controlled by the hard circuit. The valve activity experiment solenoid valve is powered by 24VDC power supply from another power conversion module, ensuring the relative of the experimental circuit and the control circuit. Independence.
3.4 Sequential Control and MCS System In order to achieve energy conservation and consumption reduction, the condensate pump is transformed with the DCS retrofit. The condensate pump frequency conversion retrofit equipment is provided by Beijing Leader Huafu Electric Technology Co., Ltd., and mainly includes the frequency conversion cabinet and the coordinated control cabinet. Its main controller selects the European T2550, which facilitates the user's on-site configuration and on-site monitoring. Remote start and stop adjustment and frequency conversion feedback signals are connected through hard wiring, and the sequence protection function will be realized by the DCS control system.
The vibration detection of the fan is also selected by Phillips's MMS60OO system, and the card components and on-site measurement components of the cabinet are simultaneously modified and replaced. The fan vibration measurement consists of an integrated integrated module EPROMMS3120 and a measuring probe PR9268. The blower, primary fan, induced draft fan, and vane probe originally had only a single X-direction measurement, and now all increased Y-direction Watt vibration measurement to achieve full-spectrum vibration monitoring. The original vibration measurement element of the exhaust air blower and the powder discharge fan is a vibration switch, and the monitoring is not intuitive. Now, after canceling the vibration switch, the PR9268 speed sensor is uniformly replaced. The continuous vibration output value of the fan vibration cabinet is used for DAS display, and its relay output vibration high signal is used for fan protection.
The milling optimization system mainly includes a coal mill noise detection device and a corresponding conversion amplification controller. The original noise detection device is one set, one set for each grinding group, and the front and back side synchronization monitoring of the noise of the grinding group is realized to ensure the reasonable allocation of coal supply, air distribution ratio, etc., so that the performance of the entire grinding group To optimize and improve.
In order to protect the safety of the crew, it reduces misoperation. An additional open signal is added to the main steam power head to ensure that the open signal is a 2 to 2 logic to ensure signal accuracy. Air blower outlet, primary air fan outlet, induced draft fan outlet, air outlet secondary air damper, air preheater damper, in addition to the original internal trip switch open signal, but also in the external baffle mechanical transmission connecting rod part increase An open signal acts as a protection double-select signal for the open signal. In addition, some electric heads have been added with electrical signals for the valve.
As the 3 # unit 1 # feed pump synchronized electric pump to steam pump work. Therefore, the corresponding DCS part increased the servo card and LVDT valve position loop, logically increased the MEH steam feed water pump control system.
In order to meet the requirements of comprehensive monitoring, some testing points have also been added. Such as demineralized water pressure, exhaust air flow.
For some important analog parameters, signal isolation devices have also been added to prevent signal interference.
3.5 The FSSS system and the DCS retrofitting will be completed with a small oil gun fuel saving retrofit project. The completed micro oil combustion function will be realized by the DCS control system. The small oil gun reconstruction project is divided into C, G layers, a total of 4 oil guns, and 4 local control boxes are installed in place. The small oil gun fire detection adopts visible light flame detection. The hard oil gun group's hard-loop function is realized by the local control box. The DCS completes remote group control and input protection logic.
In order to monitor the temperature of the boiler furnace, the system was originally installed with 4 photoelectric pyrometers, the transformation of the increase of 4 so that the boiler on the left and right sides of the wall to 4 to meet the operation of the combustion conditions of the overall monitoring requirements to achieve the safety and stability of the boiler combustion.
The low speed signal of air preheater has only one speed proximity switch installed in the local place. In order to ensure the validity of the signal, it is now added to two proximity switches and two to two outputs, which can effectively prevent the generation of proximity switches. Omissions, false positives caused by air conditioner parking.
The original coal mill low-pressure lube oil temperature is extremely high, and the temperature of the grinding group is low. The monitoring points are three temperature switches. Due to the large time delay of the temperature switch, the error during calibration is not easy to control and the sensitivity is poor. All the above measurement points of A and B mills are now detected by thermal resistance. The soft logic is used to realize the high and low limits of the oil temperature output. In this way, the oil temperature is continuously detected and the safety of the grinding group is protected.
3.6 IDAS and primary component reconstruction IDAS originally provided cold end compensator for ALSTO. The on-site thermocouple is converted to 4-20 mA standard signal and sent to P320 for display after being compensated. According to the transformation requirements, the local cold junction compensator is cancelled and the QD series intelligent front end produced by the Shanghai Electric Power Institute is used. There are 11 data collection front-ends on the boiler side and 13 data collection front-ends on the turbine side. Boiler-side data front-end communication uses two-way twisted-pair cables to be connected in parallel between terminals 11 and finally leads the data communication line from the front side of the furnace side 1# to the corresponding communication card of the DCS7# controller, LC and DCS to realize communication. The IDAS data communication line on the turbine side is connected to the DCS7# controller. For some important temperature measuring points, the total number of single units is 131 points, and direct temperature monitoring is performed by directly laying compensation cables from the DCS to the site.
The oil pump operating oil outlet oil temperature, the original design and installation of the GEORGIN temperature switch, in the primary component verification found that 3 temperature switches due to the pump body vibration has been damaged, taking into account the unreliability of the temperature switch, the current pump The operating oil temperature switch is replaced with a thermal resistance monitor. In addition, thermocouple modification was also performed on the air preheater guide and the support shaft oil temperature switch.
Primary wind, secondary wind measuring device original chute and wing. This transformation will be cancelled and replaced. At the same time, the straight section of the sampling pipe section was modified to reduce the sampling resistance and sampling blockage. Improve the reliability of air flow measurement.
Partial adjustment of the baffle, the original mechanical positioner, because it has been running for many years, the locator sensitivity greatly reduced, zero and so on need to be adjusted repeatedly, prone to valve position drift and so on. Some of the positioners have been replaced, and they have been uniformly converted to intelligent ABB locators to ensure flexible and reliable adjustments.
The original on-site control valve, seal oil vacuum tank oil level control valve, fixed cooling water temperature control valve, fuel atomizing steam pressure control valve, continuous row, etc., are now entering the DCS control system, eliminating the base of the regulator and achieving Remote adjustment.
Fuel flow meter retrofit. The oil return and oil flow meter is now replaced with an Emerson mass flow meter to make the fuel flow meter more accurate and reliable.
3.7 Alteration of other systems The 48VDC power supply of the second-phase circulating pump room was originally powered by the dual 220VAC AC-DC switch power supply in the cabinet and used two diode hot spares for output. The 48VDC is controlled by the DO channel output to start the relay, which in turn drives solenoid valves and other related equipment. Due to the fact that the dc room of the unit is far from the pump room, 48VDC cannot be directly supplied by the cable. Considering the possibility of failure of the power conversion card during the retrofit, the reliability of the power supply is not high. In the year of 2008, the unit was damaged due to the loss of 48VDC power in the pump room. Joint jump. For this purpose, the 48VDC power supply of the second pump room has been improved. The 48VDC dual output control output is provided through the power conversion card, but an additional 09LCC48VDC (pump room DC disk) is directly supplied. The three-way power supply uses a diode to isolate the hot standby. Access 48VDC active for monitoring.
IV. A Few Experiences in the Transformation of OCS Construction 4.1 In this DCS transformation, a large number of communication cards were used to connect with the auxiliary system. The connected system includes some electrical quantities, soot blowing, furnace tube leakage, milling optimization, IDAS ash removal, and more. By connecting with the LC module of the communication card, the corresponding connection cable is eliminated, the workload of the cable is reduced, and the cost is saved. For long-distance I/O stations, such as circulating water pump rooms and network control buildings, they are connected by optical cables. The connection of optical cables can ensure the long-distance transmission of long-distance data and reliable communication speed.
4.2 For the reserved cabinets such as high and low side cabinets, RBP2 milling optimization cabinet, TDM, etc., the data connection between them and the DCS are all hardwired to ensure the reliability of the control signal. In addition, the display function of the desulfurization booster fan system in the centralized control room is also increased and other desulfurization signals and the like are added.
4.3 The original P320 system design has an intermediate relay cabinet. The relay interfaces to field devices such as solenoid valves are in the middle relay cabinet, and the output relay is controlled by the P320. This transformation, OVAION system DOC card comes with relay output, so the solenoid valve and other cables connected to the site are now all connected to the controller cabinet, basically do not need intermediate relay cabinet transfer. There are only a few on-site solenoid valve cables. Because of the short cable length and other reasons, the intermediate relay cabinet can be used as the intermediate transfer terminal box for this part of the cable, and then the output can be controlled through the connecting cable.
4.4 Intermediate terminal box problem. Due to the different distribution of the old and new cabinets and the differences in the cable orientations, the length of some of the original cables to the new cabinet location is not enough. In view of this, for the 20-core cable or less, the soldering method is used for extended connection in principle. For cables with 20 cores or more, the cable is connected in the form of an intermediate transfer terminal box. For most of the 20 cores or more cables, there is a single cable to several different controller cabinets, so it is possible to lay small cables with different number of cores for different controller cabinets so that the cabinets will not be split again. .
4.5 This DCS reconstruction Uniformly draws the construction wiring diagram with MicrosftVisio. Visio is easy to operate and the components are powerful.
Make the wiring with SD diagram simple and intuitive, easy construction and wiring. However, due to the characteristics of the SD map, there are certain difficulties in querying the summary data, and sometimes the search problem is somewhat inconvenient. When the old cable marking assigns a new position, because the new IO point of the old IO point can not realize the relevant data connection, our technical personnel has used the intelligent statement to perform database data matching and manual verification. This workload is also very difficult, but In the end, the cable was never lost and correctly allocated.
4.6 As it is a retrofit project, there is no design unit between the constructor and the owner. Caused some of the point wiring diagram error, few cores and duplicate cores and other issues. For the DO output active point, passive point, AI point within the power supply, external power supply to grasp the degree of design is not enough, resulting in a certain amount of rework. In addition, both parties also conducted detailed design of hard-point connections for the interface parts such as MCS and FSSSSCS.
4.7 The DCS transformation of the two units in the second phase involves IO points of 2×6100 points and public system IO of 1800 points. A single unit retains 1,500 cables, nearly 200 cables are laid between the cables, and nearly 200 cables are newly laid to local temperatures. Since most of the DCS retrofitting cables in the original unit had problems such as cable branching, partitioning, and sub-distribution, considerable difficulties were caused in wiring the construction. Under the constant efforts of the construction technology and wiring personnel, it was successfully completed. Wiring task.
4.8 Since Phase 2 3#4# unit and public system are imported complete sets of equipment from French ALSTOM, the DCS configuration is based on the original design and features of the unit. Based on the original design function of the control system, the logic function is now optimized. The safety/reliability has been further improved.
V. Concluding remarks The DCS transformation of No. 3#4# of the second phase of Lushui Power Plant, from the dismantling of the old system to the installation and commissioning of the new system, was completed and the unit was put into normal operation, which lasted for 90 days. From the perspective of the transformation, the quality and effect are still satisfactory to all parties, and the intensity of supervision of the operating personnel is greatly reduced, which facilitates the monitoring of the operating personnel. Facts have proved that the integrated transformation of the DCS electric, furnace and public utilities for No. 3 Unit 4# unit of Luan Power Plant was completely successful.
In the past ten years since the unit was put into operation, with the upgrading of some local equipment, the unit control system was in urgent need of upgrading and capacity expansion, but the P320 system could not meet the need for open upgrade and expansion of the unit due to the lack of scalability. Coupled with the P320 system control card aging serious, spare parts purchase difficulties and a series of reasons. In order to facilitate the unified management of the whole plant, ensure the safety of the unit, and reduce the burden on the operation and maintenance of personnel, it was decided to reconstruct the DCS in the second phase.
Second, the system outline Second phase of DCS transformation selected the United States Westinghouse's OVATION control system. Its biggest feature is that OVATION adopts true open computer technology. Data networks are connected in a redundant manner. Redundant configurations such as controllers and power supplies are used to control the failure of any component in the system, without affecting the entire system. System work. OVATION has a rich set of algorithms and application software. It uses related database technology and Powertools tools that are in line with today's popular software design to make configuration more convenient. It is easy to configure, easy to expand, and easy to use. OVATION also provides comprehensive data monitoring functions, as well as historical data, data trend information, human-machine interface is more friendly, and can provide the unit with the best operating control environment to ensure that the unit operates in the best condition.
OVAT10N concentrates on DAS, SCS, FSSS, MCS, ECS, DEH, ETS, MEH and other functions. The control of the two unit units is realized by two sets of DCS respectively. The public system (circulation pump room, fuel pump room, air compressor, public The power supply system, network control system, etc. are controlled by the DCS public system (in which the remote I/O cabinets are also installed in the circulating pump room, network control building and fuel pump room fuel delivery system respectively), and the DCS public systems are connected separately. Into the DCS network of two unit units.
Unit unit system includes 12 workstations, namely 7 operator stations (including 1 large-screen operation station), 1 server/engineering station, 1 history station, 1 OPC server, 1 SIS communication management station, including 18 controller cabinets, H extension cabinets, 1 relay cabinet, 1 MFT trip cabinet, 2 power cabinets, 1 switch cabinet, and 5 reserved cabinets.
The public system includes: 1 electrical operator station, 3 controller cabinets, 2 expansion cabinets, 2 remote cabinets, 2 power cabinets, and 1 switch cabinet.
Apart from the steam drum water level CRT and the furnace flame CRT, the unit unit only has a small amount of conventional digital display meter and light card, and two large screens at the same time. As a back-up operation, the operator's station and the vertical plate still retains the boiler MFT, the turbine opening, the small engine tripping, the generator group emergency trip, and the important oil pump hard start button.
Third, the characteristics of the OCS system transformation 3.1 Power supply and grounding system UPS220VAC power from the electricity into the DCS's two power distribution cabinets, and then by the A, B power cabinets to allocate all the way to the same power controller cabinet, to achieve power redundancy Configuration. Each controller cabinet power module has a protection alarm function. The 24VDC output from the power module is used for the loop circuit of the analog loop power supply and the output relay, and the output 48VDC is used for the query voltage of the switching loop signal. In addition, according to the characteristics of the field devices, the external 48VDC supplied from the electric DC room is connected to the corresponding busbars of the cabinets, and the external 48VDC power supply is connected to the air switches corresponding to each output DOC card in parallel by the busbars. The line directly drives the field circuit. In this way, the isolation of the drive power between the DOC cards is realized, and the accidental wave caused by the single loop trip is reduced. Taking into account the actual operation of the equipment, the electromagnetic valve of the deaerator, the water supply and the furnace pump accident cooling valve three solenoid valve drive circuit, and the external supply 48VDC separate air-distribution output. Each externally supplied 48VDC busbar circuit and each digital output DOC card open circuit are designed with monitoring relays and auxiliary contacts to provide the corresponding 48VDC power supply signals.
According to the system requirements, the single point to ground resistance of the cabinet is less than 1Ω. The set of DCS systems has only one unified common ground, namely electrical ground. Electrically distinguishable are DCCOM and ACCOM, ie DC and AC grounds. ACCOM is used for the shielding of external weak signals, such as thermocouples, thermal resistance, current signals, etc. ACCOM provides a low-impedance discharge channel for fault currents and high-frequency noise, making the device housing and the ground at the same potential. The DCCOM is used as a common ground negative terminal for the 48VDC, 24VDC DC power supply. It establishes a zero potential reference point for the system's digital process control, and it can also effectively eliminate high frequency noise. In fact, DCCOM and ACCOM have interconnected in the DCS controller cabinet. In the system controller cabinets and expansion cabinets, DCCOM is interconnected by star connection. This method of connection can avoid system-wide defects caused by the disconnection of a certain link in the middle of the connection; and ACCOM is only used as Shielding ground, so its connection is designed to be connected to the interconnection between the disk.
3.2 TSI system transformation TSI system originally selected the United States BENTLY company complete sets of products. According to the design requirements, the Phillips MMS6000 system is now uniformly selected. At the same time, the cabinet card and on-site TSI measurement probes are to be modified and replaced.
3.2.1 The rotational speed measuring device, originally a three-speed-speed generator, is now to be removed and replaced. Uniformly replaced with 8 reluctance speed probes PR9376, of which 3 speed probes are used for TSJ overspeed protection, 3 probes are used for DEH speed reference signal, 1 probe is used for zero speed start and stop disc brakes, 1 probe is used In the head tachometer display.
3.2.2 The axial displacement device was originally a single eddy current probe measurement. In order to ensure the safety of the unit, it is replaced by three eddy current probes. The signal of the probe is PR6423. After the three measurement channels process the on-site signal, they are connected through a hard circuit with 3 options and 2 logic connections. The output hard contacts directly interrupt the turbine.
3.2.3 In the original TSI system, only the Y direction bearing is vibrated by the axis vibration signal. In this modification, X-axis vibration probes have been newly installed in the field. The probe model is PR6423, and the analog output value can be sent directly to the DAS system for display and analysis alarms. In this way, on-line monitoring of shaft vibration and wave vibration in the XY direction can be realized for any turbine bearing shell, which satisfies the need for full-frequency analysis of the unit.
3.2.4 According to the reconstruction plan, other differential expansion probes (3 sets), key phase probes (1 set), vibration probes (16 sets), and eccentric probes (1 set) were all replaced. The on-site transfer terminal box, probe mounting bracket, and probe displacement conversion device were also partially replaced, and some of the speed cables were re-placed.
3.3 DEH system The DEH system of the second stage of the Sulfo-power plant includes a series of functions such as OPC, BTC, ATC, TSI, ETS, and VMDS. The main steam turbine control system before the transformation consists of the following components:
3.3.1GSEOOIAR cabinet is the steam security cabinet, including ETS, adjustable door activity experiments and other functions.
3.3.2 GMA00lAR cabinet is a body measuring cabinet containing the temperature and pressure detection points of the turbine body.
3.3.3 GREO01lAR, GRE002AR, GRE003AR Cabinets, AGC, Door-to-door Control, Unit-uploading, and other functions. In this DCS transformation, the AGC function has already been moved to the MCS, and the rest of the system is ready to be removed and incorporated into the new DEH. The control function of the original DEH control Ml-CROREC is now realized by the OVATION control system.
However, in the actual simulation adjustment experiment process, due to the electro-hydraulic servo drive card provided by OVATION company, the maximum output of the regulating valve electric/hydraulic drive current can only reach about ±40mA, while the original AL-STOM company's complete set of supporting high and medium turbines The control driving current of the pressure regulating valve needs to be about ±600mA, and the servo cards supplied by OVATION cannot output such high electric/hydraulic servo drive current. This consideration was added to the mid-level driver amplification in the new DEH, and it was considered that the system security was unstable and only abandoned. The final connection scheme is to retain the original RBP2 door positioning control cabinet, ie, the mechanical measurement system and valve position system in the electro-hydraulic control system are retained. Instead, DCS provides standard current drive control signals that are hard-wired to RBP2, and then the original RBP2 system is responsible for proportional amplification, and then used for output to drive the turbine high and low pressure regulators.
Some of the original DEH's important pressure measurement transmitters are designed as single measurements. According to the requirements of the transformation, they are now uniformly added to three measurements. The main parameters added are condenser vacuum, turbine lubricant pressure, high pressure cylinder exhaust pressure, first stage steam pressure of the high pressure cylinder, steam pressure before the steam turbine main valve, inlet pressure of the lower part of the medium pressure cylinder, etc. The three measurement points are output by the logic 3, 2 and comparison to ensure the reliability of the important parameter measurement.
The ETS system is directly incorporated into the DEH instead of a separate PLC-type ETS. The logic function of the ETS is realized by the DEH, and the configuration of the main protection function of the turbine is intuitive and concise. The solenoid valve circuit in the disk is powered by two independent 24VDC power conversion modules. The solenoid valve is controlled by the hard circuit. The valve activity experiment solenoid valve is powered by 24VDC power supply from another power conversion module, ensuring the relative of the experimental circuit and the control circuit. Independence.
3.4 Sequential Control and MCS System In order to achieve energy conservation and consumption reduction, the condensate pump is transformed with the DCS retrofit. The condensate pump frequency conversion retrofit equipment is provided by Beijing Leader Huafu Electric Technology Co., Ltd., and mainly includes the frequency conversion cabinet and the coordinated control cabinet. Its main controller selects the European T2550, which facilitates the user's on-site configuration and on-site monitoring. Remote start and stop adjustment and frequency conversion feedback signals are connected through hard wiring, and the sequence protection function will be realized by the DCS control system.
The vibration detection of the fan is also selected by Phillips's MMS60OO system, and the card components and on-site measurement components of the cabinet are simultaneously modified and replaced. The fan vibration measurement consists of an integrated integrated module EPROMMS3120 and a measuring probe PR9268. The blower, primary fan, induced draft fan, and vane probe originally had only a single X-direction measurement, and now all increased Y-direction Watt vibration measurement to achieve full-spectrum vibration monitoring. The original vibration measurement element of the exhaust air blower and the powder discharge fan is a vibration switch, and the monitoring is not intuitive. Now, after canceling the vibration switch, the PR9268 speed sensor is uniformly replaced. The continuous vibration output value of the fan vibration cabinet is used for DAS display, and its relay output vibration high signal is used for fan protection.
The milling optimization system mainly includes a coal mill noise detection device and a corresponding conversion amplification controller. The original noise detection device is one set, one set for each grinding group, and the front and back side synchronization monitoring of the noise of the grinding group is realized to ensure the reasonable allocation of coal supply, air distribution ratio, etc., so that the performance of the entire grinding group To optimize and improve.
In order to protect the safety of the crew, it reduces misoperation. An additional open signal is added to the main steam power head to ensure that the open signal is a 2 to 2 logic to ensure signal accuracy. Air blower outlet, primary air fan outlet, induced draft fan outlet, air outlet secondary air damper, air preheater damper, in addition to the original internal trip switch open signal, but also in the external baffle mechanical transmission connecting rod part increase An open signal acts as a protection double-select signal for the open signal. In addition, some electric heads have been added with electrical signals for the valve.
As the 3 # unit 1 # feed pump synchronized electric pump to steam pump work. Therefore, the corresponding DCS part increased the servo card and LVDT valve position loop, logically increased the MEH steam feed water pump control system.
In order to meet the requirements of comprehensive monitoring, some testing points have also been added. Such as demineralized water pressure, exhaust air flow.
For some important analog parameters, signal isolation devices have also been added to prevent signal interference.
3.5 The FSSS system and the DCS retrofitting will be completed with a small oil gun fuel saving retrofit project. The completed micro oil combustion function will be realized by the DCS control system. The small oil gun reconstruction project is divided into C, G layers, a total of 4 oil guns, and 4 local control boxes are installed in place. The small oil gun fire detection adopts visible light flame detection. The hard oil gun group's hard-loop function is realized by the local control box. The DCS completes remote group control and input protection logic.
In order to monitor the temperature of the boiler furnace, the system was originally installed with 4 photoelectric pyrometers, the transformation of the increase of 4 so that the boiler on the left and right sides of the wall to 4 to meet the operation of the combustion conditions of the overall monitoring requirements to achieve the safety and stability of the boiler combustion.
The low speed signal of air preheater has only one speed proximity switch installed in the local place. In order to ensure the validity of the signal, it is now added to two proximity switches and two to two outputs, which can effectively prevent the generation of proximity switches. Omissions, false positives caused by air conditioner parking.
The original coal mill low-pressure lube oil temperature is extremely high, and the temperature of the grinding group is low. The monitoring points are three temperature switches. Due to the large time delay of the temperature switch, the error during calibration is not easy to control and the sensitivity is poor. All the above measurement points of A and B mills are now detected by thermal resistance. The soft logic is used to realize the high and low limits of the oil temperature output. In this way, the oil temperature is continuously detected and the safety of the grinding group is protected.
3.6 IDAS and primary component reconstruction IDAS originally provided cold end compensator for ALSTO. The on-site thermocouple is converted to 4-20 mA standard signal and sent to P320 for display after being compensated. According to the transformation requirements, the local cold junction compensator is cancelled and the QD series intelligent front end produced by the Shanghai Electric Power Institute is used. There are 11 data collection front-ends on the boiler side and 13 data collection front-ends on the turbine side. Boiler-side data front-end communication uses two-way twisted-pair cables to be connected in parallel between terminals 11 and finally leads the data communication line from the front side of the furnace side 1# to the corresponding communication card of the DCS7# controller, LC and DCS to realize communication. The IDAS data communication line on the turbine side is connected to the DCS7# controller. For some important temperature measuring points, the total number of single units is 131 points, and direct temperature monitoring is performed by directly laying compensation cables from the DCS to the site.
The oil pump operating oil outlet oil temperature, the original design and installation of the GEORGIN temperature switch, in the primary component verification found that 3 temperature switches due to the pump body vibration has been damaged, taking into account the unreliability of the temperature switch, the current pump The operating oil temperature switch is replaced with a thermal resistance monitor. In addition, thermocouple modification was also performed on the air preheater guide and the support shaft oil temperature switch.
Primary wind, secondary wind measuring device original chute and wing. This transformation will be cancelled and replaced. At the same time, the straight section of the sampling pipe section was modified to reduce the sampling resistance and sampling blockage. Improve the reliability of air flow measurement.
Partial adjustment of the baffle, the original mechanical positioner, because it has been running for many years, the locator sensitivity greatly reduced, zero and so on need to be adjusted repeatedly, prone to valve position drift and so on. Some of the positioners have been replaced, and they have been uniformly converted to intelligent ABB locators to ensure flexible and reliable adjustments.
The original on-site control valve, seal oil vacuum tank oil level control valve, fixed cooling water temperature control valve, fuel atomizing steam pressure control valve, continuous row, etc., are now entering the DCS control system, eliminating the base of the regulator and achieving Remote adjustment.
Fuel flow meter retrofit. The oil return and oil flow meter is now replaced with an Emerson mass flow meter to make the fuel flow meter more accurate and reliable.
3.7 Alteration of other systems The 48VDC power supply of the second-phase circulating pump room was originally powered by the dual 220VAC AC-DC switch power supply in the cabinet and used two diode hot spares for output. The 48VDC is controlled by the DO channel output to start the relay, which in turn drives solenoid valves and other related equipment. Due to the fact that the dc room of the unit is far from the pump room, 48VDC cannot be directly supplied by the cable. Considering the possibility of failure of the power conversion card during the retrofit, the reliability of the power supply is not high. In the year of 2008, the unit was damaged due to the loss of 48VDC power in the pump room. Joint jump. For this purpose, the 48VDC power supply of the second pump room has been improved. The 48VDC dual output control output is provided through the power conversion card, but an additional 09LCC48VDC (pump room DC disk) is directly supplied. The three-way power supply uses a diode to isolate the hot standby. Access 48VDC active for monitoring.
IV. A Few Experiences in the Transformation of OCS Construction 4.1 In this DCS transformation, a large number of communication cards were used to connect with the auxiliary system. The connected system includes some electrical quantities, soot blowing, furnace tube leakage, milling optimization, IDAS ash removal, and more. By connecting with the LC module of the communication card, the corresponding connection cable is eliminated, the workload of the cable is reduced, and the cost is saved. For long-distance I/O stations, such as circulating water pump rooms and network control buildings, they are connected by optical cables. The connection of optical cables can ensure the long-distance transmission of long-distance data and reliable communication speed.
4.2 For the reserved cabinets such as high and low side cabinets, RBP2 milling optimization cabinet, TDM, etc., the data connection between them and the DCS are all hardwired to ensure the reliability of the control signal. In addition, the display function of the desulfurization booster fan system in the centralized control room is also increased and other desulfurization signals and the like are added.
4.3 The original P320 system design has an intermediate relay cabinet. The relay interfaces to field devices such as solenoid valves are in the middle relay cabinet, and the output relay is controlled by the P320. This transformation, OVAION system DOC card comes with relay output, so the solenoid valve and other cables connected to the site are now all connected to the controller cabinet, basically do not need intermediate relay cabinet transfer. There are only a few on-site solenoid valve cables. Because of the short cable length and other reasons, the intermediate relay cabinet can be used as the intermediate transfer terminal box for this part of the cable, and then the output can be controlled through the connecting cable.
4.4 Intermediate terminal box problem. Due to the different distribution of the old and new cabinets and the differences in the cable orientations, the length of some of the original cables to the new cabinet location is not enough. In view of this, for the 20-core cable or less, the soldering method is used for extended connection in principle. For cables with 20 cores or more, the cable is connected in the form of an intermediate transfer terminal box. For most of the 20 cores or more cables, there is a single cable to several different controller cabinets, so it is possible to lay small cables with different number of cores for different controller cabinets so that the cabinets will not be split again. .
4.5 This DCS reconstruction Uniformly draws the construction wiring diagram with MicrosftVisio. Visio is easy to operate and the components are powerful.
Make the wiring with SD diagram simple and intuitive, easy construction and wiring. However, due to the characteristics of the SD map, there are certain difficulties in querying the summary data, and sometimes the search problem is somewhat inconvenient. When the old cable marking assigns a new position, because the new IO point of the old IO point can not realize the relevant data connection, our technical personnel has used the intelligent statement to perform database data matching and manual verification. This workload is also very difficult, but In the end, the cable was never lost and correctly allocated.
4.6 As it is a retrofit project, there is no design unit between the constructor and the owner. Caused some of the point wiring diagram error, few cores and duplicate cores and other issues. For the DO output active point, passive point, AI point within the power supply, external power supply to grasp the degree of design is not enough, resulting in a certain amount of rework. In addition, both parties also conducted detailed design of hard-point connections for the interface parts such as MCS and FSSSSCS.
4.7 The DCS transformation of the two units in the second phase involves IO points of 2×6100 points and public system IO of 1800 points. A single unit retains 1,500 cables, nearly 200 cables are laid between the cables, and nearly 200 cables are newly laid to local temperatures. Since most of the DCS retrofitting cables in the original unit had problems such as cable branching, partitioning, and sub-distribution, considerable difficulties were caused in wiring the construction. Under the constant efforts of the construction technology and wiring personnel, it was successfully completed. Wiring task.
4.8 Since Phase 2 3#4# unit and public system are imported complete sets of equipment from French ALSTOM, the DCS configuration is based on the original design and features of the unit. Based on the original design function of the control system, the logic function is now optimized. The safety/reliability has been further improved.
V. Concluding remarks The DCS transformation of No. 3#4# of the second phase of Lushui Power Plant, from the dismantling of the old system to the installation and commissioning of the new system, was completed and the unit was put into normal operation, which lasted for 90 days. From the perspective of the transformation, the quality and effect are still satisfactory to all parties, and the intensity of supervision of the operating personnel is greatly reduced, which facilitates the monitoring of the operating personnel. Facts have proved that the integrated transformation of the DCS electric, furnace and public utilities for No. 3 Unit 4# unit of Luan Power Plant was completely successful.
Jilin Province Xuan Yi Trading Co.,Ltd. , https://www.jlxytruckpart.com