Activities of the Japanese ATP User Group (JAUG) on the Internet

Activities of the Japanese ATP User Group (JAUG) on the Internet and Current Status of ATP in East Asia

Tsuyoshi Funaki Yasuhide Kashiwagi Masahiro Kan Hiroshi Arita

Osaka Univ. Kisarazu N.C.T. Toshiba Corp. Hitachi, Ltd.

Electrical Eng. Dept. Dept. of Electrical and Electronic Eng. Surge Arrester Dept. Power & Industrial Systems R&D Lab.

2-1 Yamada-oka, Suita, Osaka Kiyomidai-Higashi, Kisarazu Hamakawasaki Operations 7-2-1, Omika-cho, Hitachi-shi

565-0871 Japan 292-0041 Japan 210-0862 Japan Ibaraki-ken, 319-1221 Japan

Abstract – Japanese ATP User Group (JAUG) has greatly November 1997, whose objectives are as follows; contributed to the improvement of the license management, - to approve the license application, and to manage the ATP program distribution, exchanging information among users in license, on behalf of the copyright holder(Can/Am EMTP User East Asia as well as in Japan, through the positive utilization of Group) the Internet. As a result, the number of ATP users is steadily - to popularize the ATP increasing both in Japan and East Asia. JAUG also has promoted - to facilitate information exchange and distribution the development of ATP according to the recent requirements - to distribute the ATP program and related materials from users, and some new functions useful for the ATP analysis - to promote the improvement and enhancement of ATP have been developed. JAUG is intended to make the most of the Internet. On its re- Keywords: ATP, EMTP, JAUG establishment, the authors provisionally became the Secretary of the JAUG and they were reelected by a confidence vote to a

1. INTRODUCTION second term. Voting for a chairman was done through the ATP (Alternative Transients Program) is a non- Internet by a voting home page, which was the first attempt commercialized version of the EMTP (Electro Magnetic among ATP user groups to use such a method. Transients Program), which works on IBM/AT compatible PCs.

JAUG is responsible for ATP users in Japan and in some parts of 2.1 Information offering East Asia. This paper describes the Internet service of ATP JAUG offers information about the ATP related matters on its related issues produced by JAUG. While details are described in home page. They include descriptions about ATP, program the paper, there may be differences from the WWW site contents, copyrights, how to get license and resources, supporting because the latter are dynamically updated from one hour to the platforms, questions, and links to other related sites etc. Newly next which makes the most of Internet merits. This paper also developed functions, which are described in the following introduces the current status of ATP users and distributions in section in this paper, are also introduced and they are updated East Asia. Lastly, this paper describes recent technology trends whenever changes occur or bugs are detected and/or fixed. related to ATP.

2.2 Resource distribution 2. JAUG ACTIVITIES ON THE INTERNET JAUG distributes ATP resources including the program itself, JAUG (Japanese ATP User Group) [1-3] was re-established in manuals, benchmarks, and other documents to licensed users. All r 200 e b

m 150 Year u n Total d

e 100 s n e

c 50 i L 0 1993 Year 1996 1999 (a) Licensed number in Japan 90

r 80 e b 70 m u

e 50 s n

e 40 c i l

30 l a t 20 o

T 10 0 1990 1993 Year 1996 1999 India and Sri Lanka Malaysia P. R. China Bangladesh Singapore Thailand Philippines Indonesia Bahrain Vietnam (b) Licensed number in East Asia Fig. 2. Number of ATP licenses in Ease Asia.

The ATP license is granted by submitting an application form to the JAUG Secretary by conventional mail. This submitting

Fig. 1. JAUG Internet servers and user groups in the world. procedure may become electronic with progress in electronic authentication technology. The confirmation mail, which describes the conditions to join the password notifications list to these can be got by FTP through the Internet, though they are access ATP resources and information exchanging board, will be password protected. The location and relation between servers sent to the applicant when the license is approved. When the and JAUG connections worldwide servers are depicted in Fig.1. applicant agrees to the conditions, the password is given. New passwords are automatically distributed when one is changed.

2.3 Information interchange board Fig.2 (a) shows the license number in Japan from 1993 to 1999. The WWW Board was established to offer the secure The total approved license number reached 170 in April 2000. discussion forum protected by a password. It promotes the information exchange among ATP users and it also offers a first- 3. ATP USERS IN EAST ASIA time guide, Q&A to introduce ATP. The users can easily trace the Presently, there are four ATP user groups in East Asia. They discussion afterwards, and it enables to avoid repeated similar are JAUG (Japan), KAUG (South Korea), CAUG (Taiwan) and questions. IAUG (India). The respective user groups take care of users in each country. In addition, JAUG takes care of not only the

2.4 JAUG service on license approval and password Japanese users but also the users in other countries who do not the description inside. Node name conflicts among internal descriptions of modules do not occur when using the same module repeatedly in the circuit. Then the Data Base Module can be effectively used in describing the system having multiples of the same circuits and control blocks, such as HVDC systems etc.

Fig. 3. A circuit image created by ATP Draw. Though ATP Draw cannot draw the description of the Data Base Module itself, use of a model is available in the GUI, which is similar to the basic components, when the module is prepared as have their own user group in East Asia. Fig. 2(b) shows the a User Specified Model in advance as shown in Fig. 3 [4]. license number change during the last decade in East Asia. The user number in Japan is the largest in East Asia. The newly 4.2 GIFU switch (logic for on/off decision) licensed number in Japan has steadily increased since 1997. The EMTP was developed for simulation and analysis of surge license number has tended to increase in most other countries, phenomenon at its beginning. It was not designed to analyze the especially India and Sri Lanka. The number reached 20 licenses behavior of power electronics converters, which consisted of in P.R. China after JAUG was re-established. JAUG treats the multiple switching devices such as HVDC or FACTS. The on/off ATP license as a site license, to reduce work procedures for the status and state transition of diodes and thyristor valves are Secretary, which is voluntary. The actual user number is several decided by their branch voltage or node current, and their or several tens of times greater than the number of licenses, switching behavior make sense to the analysis by delaying one because the members in the organizations are using ATP under calculation time step after the switching transition event the control of the representative who signed the license. JAUG occurrence. This switching state decision logic may cause an will request establishment of a user group in a country when inadequate combination of switching states and circuit users in the country exceed some value. configuration, which may not occur in an actual circuit, when employing plural switching devices to circuits like a power

4. NEW ANALYSIS FUNCTIONS OF ATP electronics converters. In the worst case, the simulation may be 4.1 Data Base Module terminated, because of the occurrence of an independent circuit The input data cards of the EMTP type simulation program having floating nodes. This difficulty can be avoided by adopting must be written obeying a strict syntax formality of fixed data a snubber circuit in parallel to the switching devices, which column position and length. It is hard for EMTP beginners to allows the calculation to continue. But the circuit constant of the write data cards. ATP offers the GUI developing environment snubber circuit in the analysis becomes quite different from that tool called “ATP Draw”, which assists in data card generation. It of the actual one, and the simulation results are far from realistic. helps beginners to build circuits and control blocks more easily The newly developed and improved ATP switching decision and intuitively. On the other hand, ATP Draw can handle tasks up logic performs iterative calculations to judge the on/off to only 1000 nodes and it is insufficient for a large-scale circuit conducting state of the switching devices without time delay. It is description. The Data Base Module function of ATP can arrange realized by going back to the previous calculation time step when a module and make the data cards together for each functional switching state transitions occur. This was proposed by Prof. block. It enables the module to be used easily as a functional Murai (Gifu Uinv.) and this switching decision logic is called a block through input and output nodes without paying attention to “GIFU switch” [5]. The switch makes it possible to analyze power electronics circuit with better agreement to the circuit analogue computer in the analysis which describes the control behavior. On the other hand, the difficulty of numerical block of the power apparatus and which runs independently of oscillation occurrence at the inductance and capacitance caused the circuit calculation. The TACS function can describe not only by the switching transient, which is unavoidable for the EMTP transfer functions, but also various complex formulas using a that uses a trapezoidal rule as a numerical integration method, FORTRAN expression in free format. This FORTRAN has been pointed out. Discussions about the necessity of expression can be used to describe and analyze transient calculation algorithm improvement are very active now. phenomenon, whose characteristics can be formularized by non linear equations. But this requires huge amount of TACS

4.3 Higher-order Pi circuit statements, which destroys the readability and maintainability The electromagnetic couplings among conductors must be and may easily lead to mistakes. Compiled TACS enables a taken into account when precisely analyzing the electromagnetic TACS statement to call functions and subroutines, which are transient phenomena. ATP offers a mutually coupled R-L matrix written in external files in conventional FORTRAN or C circuit analysis routine, which can take into account coupling language. The complex formula can be written in external files, among overhead transmission lines and ground wires etc., so the resulting TACS statements become simple and readable, because it does not neglect the coupling effect, especially in the and as a result, maintainable. lightning surge region. Insulation arrangement among windings Reference [7] realizes improvement in the execution time and of the transformer and reactors is very important, when designing in the expression readability to the analysis of lightning induced the insulation condition of a power apparatus and it requires surge formula by making the most of Compiled TACS. analysis of the electrical potential distribution inside the TACS was sufficient for describing control blocks when apparatus. The coupling among windings of the transformer is analogue control took the leader part, but recently it has become tight because the windings are thickly wound and the insufficient since digital control has become the main stream. A electrostatic capacitance between the windings and the sample and hold function, multiplication of data and coefficients transformer cores, which have different potential, is large. and summing them by using an array variable is required to Although, connecting and coupling a pi equivalent circuit can express digital control. It becomes hard to realize such a function model them, this requires a higher order coupling expression for by TACS when high order is involved, which is similar to the precise modeling of the windings of the transformer. expression of a complex long formula described above. The conventional R-L matrix expression in the ATP can handle MODELS description is suitable for describing a digital signal- coupling up to the 40th order, and that is not enough for precise processing unit, which can execute the processing function in a modeling of the transformer. The expanded ATP for precise different time interval than the circuit calculation time step by modeling was developed which removes the limitation of the indexing the TIME STEP to the respective model, and it can order in the R-L matrix. Reference [6] confirms the validity of utilize array variables and easily express a high order system. the developed program through analyzing the 400th order pi However, the execution time of MODELS is quite slow when equivalent circuit of a transformer and by comparing the results comparing to the same function expressed by TACS, because the with other results obtained from a confidential method. former runs in the interpreter manner. Compiled MODELS was

developed to improve the execution time of MODELS by

4.4 Compiled TACS/MODELS (Model description function) implanting the required calculation routine into the ATP The TACS function of EMTP was developed to simulate an executable program and utilizing it as a foreign model or a foreign function in MODELS. improves the convergence performance of the initial power flow Reference [8] developed the interface routine of the foreign calculation for an asymmetrical system, because it performs the model and function described by C language with the ATP main power flow calculation in the three-phase circuit using a routine described by FORTRAN language to make a hybrid ATP successive current source substituting method. executable program. It also shows the application of digital signal processing in ATP by using compiled MODELS and 5. CONCLUSIONS calculation time improvement. This paper reported activities of JAUG and its Internet services. The information about the ATP current status in East

4.5 TYPE58 S.M. Model Asia was also given. This paper also introduced about the newly The conventional Type 59 synchronous machine (S.M.) developed ATP functions. These new functions of ATP are being model of ATP is modeled by using Park’s equation, which is improved and the web site presents this new information. based on the d-q-0 rotating frame reference. This synchronous Don’t forget to check this URL! machine model is represented by the Thevenin equivalent circuit http://www.jaug.gr.jp/ whose values are calculated from the estimated value of the rotating speed of the rotor, speed voltage and current at the REFERENCES terminal to interface the model output in sequence system with the network of a three-phase circuit. This model has a problem of [1] T. Funaki et al. ,”Establishment of Japanese ATP (Alternative numerical instability caused by the estimation error. Transients Program) User Group”, 1999 National Convention

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