ATP-EMTP is also equipped with a graphic input program ATPDrawTM, and the latest version is 1.4. ATPDraw 1.4 is a 32-bit program, which can run under Windows95/NT. As a preprocessor of ATP-EMTP, ATPDraw finally generates a properly formatted ATP-EMTP data input file. At present, ATPDraw supports 70 standard components and 28 TACS modules, and also supports models. Users can create them according to their own needs. Hey? Sangfang? Hey? At present, the mathematical models of ATP-EMTP include the following:
Lumped parameter resistance r, inductance l and capacitance c;
● Polyphase PI equivalent circuit;
● Multiphase distributed parameter transmission line;
Nonlinear resistance, in which the v-i characteristic curve is single-valued;
● Nonlinear inductance can not only simulate the conventional single-valued characteristic curve, but also include remanence and hysteresis;
● Time-varying resistance;
Switches, used to simulate the changes of circuit breakers, spark gaps and other network connections, including diodes and thyristors;
● Voltage and current sources, in addition to standard mathematical function waveforms, users can also define waveforms with FORTRAN or TACS;
● Dynamic rotating motor can simulate not only the most commonly used three-phase synchronous motor, but also single-phase, two-phase, three-phase induction motor and DC motor. It is connected with TACS control system model and can simulate the dynamic characteristics of voltage regulator and governor.
The control system model can be realized by TACS (transient analysis of control system), which allows different kinds of nonlinear and logical operations. The input and output of the control system can be connected with the power grid of EMTP.
ATP-EMTP is also equipped with a model, which is a general description language that is more flexible and functional than TACS. Its function can be summarized as follows:
Provide a tool for developing circuit and control component models, which is difficult to realize with the existing component models in ATP and TACS;
● It has the flexibility of a complete programming language, and there is no need to interact with ATP programs at the programming level;
● It can describe not only how the component works, but also how the initial state of the component is established;
● At the modeling level, the standard program interface with ATP is established through voltage, current and control signals, not through variables, common data areas and subroutines at the programming level, which makes it unnecessary to understand how ATP works internally and change the ATP source program when ATP is connected with external programs. EMTP is based on trapezoidal integral rule, takes adjoint model as dynamic unit, establishes equations by node method, and solves algebraic equations by sparse matrix and LU decomposition method. The integration step size is specified by the user and remains unchanged throughout the simulation process.
Different from SPICE, the switch in SPICE is represented by nonlinear resistance, while the switch in EMTP is represented by: open circuit when disconnected; Connecting is a short circuit, and two related nodes are combined into one. EMTP has a module-to-controller simulation called TACS and a module called model. EMTP is a constantly developing software with a lot of resources, so it has become the working standard of American power system and electronic power simulation. Up to now, a number of ATP-EMTP user associations have been formed in the world, which are usually divided by regions, including:
● Canadian/American EMTP user base,
● Latin American EMTP user base,
● EEUG (European EMTP-ATP user group),
● Australian EMTP Users Association,
● South African EMTP Users Association,
● JAUG (Japanese EMTP user group),
North Korea EMTP Committee.
● China Taiwan Province EMTP User Association (including Hongkong and Singapore).
Most technical data about ATP-EMTP can be obtained through the Internet. Many ATP-EMTP users' associations have published their own magazines, recording the experience of using ATP-EMTP and the latest information about ATP-EMTP. In addition, EMTP users association encourages and supports users who have obtained the license to exchange experiences and latest information.
At 199 1, Professor BruceMork established an ATP-EMTP mailing list at the University of North Dakota. The function of mailing list is to forward the received mail to all users who participate in mailing list. At present, more than 600 users have participated in ATP-EMTPMaillist, which has become the best place for ATP-EMTP users around the world to ask questions, exchange experiences, release information and contact program developers. Anyone with an ATP license can join the mailing list.