The die
casting part production flow chart
Injection
speed of die cast process
Pouring
liquid metal tie up chamber volume percent
Injection
speed(cm/s)
≤30
30-60
>60
30-40
20-30
10-20
High
speed computing formula
V
-------------Cavity volume (CM3);
N ------------ Cavity No;
D ------------ Die-casting drift (CM);
T ------------- Proper filling time.
The production of aluminum and Zinc Alloy Die Casting parts.
A380 Aluminum Die Casting, Aluminum Die Cast Part, Die Casting Parts, Zinc Die Casting NINGBO BEILUN LEMA MACHINERY TECHNOLOGY CO.,LTD , http://www.china-lema.com
1 Application Environment The operating environment of the AGC system is the OPEN-2000 energy management system of Jiangsu Province.
a. Hardware Environment: Currently running on the ALPHA platform of the original US COMPAQ company, it can be ported to other hardware platforms as needed.
b. Operating System: Currently running in the TRUE64 UNIX software environment of the original US COMPAQ company, it can be ported to other operating systems as needed.
c. Database: Combining a commercial database with a real-time database, the Sybase commercial database is currently used and can be ported to other commercial databases as needed.
d. Development Tools: Use FORTRAN and C++ as application development tools.
2 control strategy design 2.1 AGC strategy designed according to A1, A2 AGC A1, A2 control performance evaluation standard pursuit regional control deviation (ACE) value (marked as εACE) zero-crossing in a relatively short time. The basic control strategy of the AGC system designed according to this standard is: When εACE>0, the control region will reduce the force; when εACE<0, the control region will add force.
In the AGC, the AGC software will divide the ACE into four regulation regions based on the size of the εACE and the set threshold: ACE dead zone, normal adjustment zone, secondary emergency adjustment zone (or auxiliary adjustment zone), and emergency adjustment zone. Different regulated areas may have different units to take the ACE adjustment component to achieve the optimal combination of the unit control; in addition, in different control areas, the system will adopt different AGC control strategies. If in the ACE dead zone, the regulated power of the genset is “0â€; in the emergency regulated zone, if the control target of a certain genset is not conducive to the change of the ACE to the absolute value, the control command is not issued. In this regulation area, the unit that only allows the power increment and ACE reversal (which acts to reduce the ACE amplitude) changes the output of the unit it controls, and the output of the other units remains unchanged.
2.2 CPS Control Strategy Design The CPS control performance evaluation standard seeks to maximize the CPS1 value and emphasizes the contribution of the control region to maintaining frequency quality. Can be divided into the following three kinds of situations for analysis.
a. When εACE>0, system frequency deviation △f>0, whether in order to maintain the need for regional electric power balance, ie, ACE control, or to maintain the system frequency, ie, the need for system frequency control, it is desirable to control the area reduction force. Reduce the εACE and △f values.
b. When εACE<0, △f<0, contrary to the above situation, both ACE control and system frequency control are expected to increase the force in the control region, thereby reducing the amplitudes of εACE and Δf.
In the above two cases, the control direction of the control area is the same as the control direction of the control area designed according to the A1 and A2 standards.
c. When εACE>0, △f<0 or εACE<0, △f>0, there is a contradiction between ACE control and system frequency control. At this time, the control direction of the control zone should be determined depending on the size of εACE and Δf. If εACE is large and △f is not large, ACE control is dominant; if Δf is large, system frequency control is dominant. In this case, the control direction of the control area is not the same as the control direction of the control area designed according to A1, A2 standards.
Based on the above analysis, the CPS control strategy we designed is: Apply the function of the adjustment region according to the εACE size in the AGC system designed according to A1, A2 standards, and make the following adjustments:
a. In the normal regulation region, if decreasing εACE is not favorable to the system frequency (eg, εACE<0, △f>0 or εACE>0, △f<0, ie, CPS1>200%), it will not be adjusted. The total regulated power is 0, as in the ACE deadband.
b. In the emergency and emergency control areas, when CPS1 is greater than 200% and â–³f is greater (absolute value is greater than a manually set deviation value), the system frequency deviation is mainly caused by the power shortage in other control areas. This area has made a greater contribution to the restoration of the system frequency, in order not to affect the further recovery of the system frequency, and in order not to make this control area in an unfavorable situation when the frequency recovers, so that the total power of the regional regulation is 0, as if the ACE died. District same.
c. The control strategy for other situations is the same as the A1 and A2 standards.
2.3CPS Option A switch of the CPS option is designed in the AGC system to enable the AGC system to control both the CPS standard and the A1, A2 standard control mode.
3 Deviation from planned electricity treatment technology The East China Power Grid CPS assessment method deviates from the planned electricity by a fixed 30 min as the settlement interval. Therefore, the system design deviates from the planned electricity and accumulates and repays for a given time (30 min). This time can be considered at any time considering the future development. Adjustment. The method of deviating from the planned electricity reimbursement is to set a plan reimbursement power in the calculation formula of ACE, and there are two kinds of manual and automatic repayment start-up methods.
Since the deviation from the planned electricity charge is closely related to CPS1 in the settlement interval, an exchange plan offset function is designed in this system. Using this function, the dispatcher can artificially superimpose on the exchange power plan according to the grid demand. An offset, thus controlling the deviation from the planned electricity, to obtain greater economic benefits for the company.
4AGC Performance Monitoring Design The CPS standard requires high data sampling and processing. The system design frequency deviation and ACE sampling period is 1s, then the average value of 60 values ​​are calculated to obtain the average frequency difference of 1min and the average ACE; simultaneously calculate 1min CPS1, the system also statistics 10min ACE average and CPS1, 30min CPS1 and CPS1 and CPS2 indicators that deviate from planned electricity, days, months, and years and historically preserve this information. The system design still retains the statistical results of the A1 indicator in the A system standard, and the A2 standard has the same statistical method as the CPS2. Therefore, the system adapts to both the CPS standard and the A1, A2 standard in performance monitoring.
Corresponding to East China Power Grid's CPS assessment method, the system has designed a 10-minute real-time monitoring screen for the current CPS assessment period. The content includes the ACE average value, frequency difference average, CPS1, deviation plan power, and 10 min The ACE average value, CPS1, and deviation from the planned settlement for the corresponding settlement interval allow the dispatcher to grasp the real-time running status of the AGC.
5 other new features designed 5.1 optimization of thermal power plant regulation performance design due to the inherent characteristics of thermal power units, when the load command direction changes too frequently and the unit output is constantly rising and falling alternately, the unit control system will always be in frequent Adjusting the state not only makes the unit unable to operate stably, but also affects the load regulation response of the unit and the AGC system. For this reason, the system has designed a unit reverse control delay function, that is, the reverse regulation of the unit needs to pass an artificially set time. By using this function, it is possible to make some of the units rise only at the time, while the other units will only go up and down. After an artificially set period of time, the upgraded units will become lower and the descending units will become higher. In this way, not only the adjustment performance of the unit is improved, but also the adjustment performance of the entire AGC system is improved.
5.2 Multiple data source processing technologies With the development of communication technologies, especially network technologies, there are more than one source of factory and station information data. In particular, the link gateway information includes information not only from the factory station and the higher-level dispatching department, but also from information from the opposite factory station. The plant station information includes not only conventional telecontrol agreements, but also agreements such as 101 and 104. Therefore, a gateway message may have 3 to 4 data sources. The ACE can be calculated by using the gateway information, exchange power planning values, and system frequency, and can also be obtained from the information directly from the upper-level dispatching department. In order to make full use of information resources, multiple data source processing functions are implemented in the AGC function: multiple measurements can be defined for each tie line gateway and exchange power planning values, and the direction of each measurement can be defined and can be manually And automatically switch the measurement of each gate or exchange power plan value, and automatically switch to its other measurement when a gate or exchange power plan value measurement is invalid. The ACE value can also be directly taken from the information sent by the upper department (network ACE), and the two ACE values ​​(Calculation ACE and Network ACE) can be switched manually or automatically.
5.3 Unit Tracking Curve Processing Technology In order to facilitate the operation and management of the AGC unit, the system has designed the unit tracking curve function: the system automatically records the output of each unit per minute, the dispatching load command, and the unit control mode; records the instructions issued by each unit. Information, ie the time of issuance, the dispatching load instruction and the output and control mode of the unit at that time. This information can be viewed through a historical data query in the form of a table or a curve.
6 Operational situation Power line assessment of East China Power Grid Province (city) link line The CPS standard of AGC was implemented from October 1, 2001. Due to the great contradiction between the control strategy of the original AGC system of Jiangsu Power Grid and the CPS standard, AGC for Jiangsu Power Grid Operation and statistical assessment have had adverse effects. After the AGC system adapted to the CPS standard was put into operation on December 28, 2001, through the coordination of the primary frequency modulation function of the large power grid unit, the assessment indicators of Jiangsu Power Grid CPS1 and CPS2 have been greatly improved, the frequency of responsibility assessment has been significantly reduced, and its social benefits have been reduced. Significant economic benefits. Table 1 shows the AGC operational indicators and the frequency of responsibilities assessment of Jiangsu Power Grid three months before and after the system was put into operation. 
0 Introduction China Eastern Power Grid implemented the automatic power generation control (AGC) CPS control standard on October 1, 2001, and formulated a provincial (municipal) tie-line power flow assessment method based on the CPS standard, and the current domestic and foreign energy management. The control strategy of the system (EMS) AGC software is designed according to the AGC performance evaluation standards A1, A2. According to the analysis, the control strategy of the AGC system designed according to A1, A2 standards is disadvantageous to the CPS1 index under certain circumstances. In order to adapt to the AGC CPS control standard and the East China Power Grid CPS assessment method, the Jiangsu Electric Power Dispatch and Communication Center conducted related research from the end of 2000, analyzed and discussed the characteristics of the A1, A2 and CPS1, CPS2 performance evaluation standards and the control of the power grid. Influences, for Jiangsu Province adjust OPEN-2000 system The original AGC software designed according to A1, A2 standard carries on the adjustment and the revision to the control aspect, the performance monitoring, the deviation plan electricity accumulation and the compensation and so on 3 aspects, has added some functions. 7 Conclusion The AGC system adapted to the CPS standard satisfies the needs of the Jiangsu Power Grid for assessing the AGC system based on the CPS, improves the grid frequency quality, and improves the AGC regulation quality. Its CPS control strategy is simple and effective. The system has a reasonable design, easy operation and rich functions. It is an advanced and practical AGC system.