Rectifiers & D.C. Power Supply Systems

Automated current control system for potline (ACCS-P)-roselco microscada

Application

The ACCS – P currents control system of electrolysis series is intended for setting and stabilizing the predetermined current of electrolysis series, as well as for control of this current according to the set algorithm, with the purpose to deliver the required amount of ampere – hours to Customers. It is used in converter substations furnished with thyristor sets, or diode units with saturable reactors.

ACCS – P ensures:

substantial decrease of the number of on – load tap changings;
uniform distribution of load among the units;
stabilization of electrolyzers performance;
possibility to control consumption of electric power;
reliable control of analog values and control over the state of devices incorporated by the sets;
register and keeping records on important information;
control of all series from one post;
direct access of all supervisors to entire data.

ACCS – P consists of a program control cabinet, which is installed directly in the converter substation, and the devices of the central (control) desk, which comprises: system block, colour monitor, printer for printing messages and reports.

Lower level of ACCS – P

Used for the lower level devices are SIMATIC controllers, or similar devices of other manufacturers, on Customer's choice. The base elements are agreed upon with the Customer at the time of concluding the relevant supply contract. The controller is built into control cabinet containing the following functional units:

local current setting of potline;
current regulator of potline;
regulator of ampere – hours;
overload control of rectifier sets;
on – load tap changer control;
limiting maximum voltage of potline;
control of devices incorporated by he sets.

Series interface RS 485 is used for communication with the higher level systems.

Controller in cabinet enables to assure correction of algorithm parameters and has a reserve of information capacity to improve the algorithm, being also capable of exchanging information in between the machines.

Upper level of ACCS – P

Upper level of ACCS – P system is realized on the basis of IBM – compatible personal computer linked with cabinet controllers by way of series channels for information exchange. The state of technological process is depicted on the computer display in the form of graphic mnemonic snaps. The values of various parameters are displayed on them in the form of numerals, change of colour, size, shape, location spot, figure outlines, etc.

Upper level of ACCS – P allows:

to correct adjustment of ACCS – P;
to scan alarm and warning messages;
to plot the graphs of file – stored parameter histories;
to perform routine switching;
to have prompt information on state of the rectifier sets and incorporated devices;
to produce and scan the reports, etc.

Provision is made for wide use of snaps with different prompts to an operator in some or other situations.

The process control functions may be considerably extended and modified on requests of individual Customers.

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