scope:

FOREWORD

The continuing expansion and modernization program in the cement industry has placed an increasing importance on the cement plant power distribution system. Increasing plant capacity accompanied by larger kilns, grinding mills, crushers, and the increasing use of automatic controls has placed greater stress on the adequacy and reliability of the distribution system. Safety, capacity, reliability, and low maintenance-all at a reasonable cost-are the requirements of the cement plant power distribution system.

It was for the purpose of establishing recommended practices for the cement industry to realize these requirements that the Distribution Working Group of the Cement Industry Committee was formed. The Working Group undertook this task in 1959.

The first report of the Distribution Working Group was titled "Report on Preliminary Suggested Recommendations for Cement Plant Power Distribution" and was prepared for publication and presentation at the Milwaukee, Wisconsin 1960 Technical Conference sponsored by the AIEE Cement Industry Committee. As a result of the comments received at annual Conferences, the report has been revised and expanded each year. It now includes recommendations on the main plant substation, high-voltage distribution, relaying, metering, cables, lowvoltage distribution, and quarry distribution.

The recommendations given in this Recommended Practice are those on which the Distribution Working Group could reach an agreement. Certainly, any unusual conditions prevailing in a particular plant may change the advantages or disadvantages usually realized for a particular scheme. The IEEE Standards Publication, No. 141, titled "Electric Power Distribution for Industrial Plants," brings to attention the important features of well-designed electric distribution systems that result in satisfactory performance of utilization equipment and efficient operation of plants in general. It is hoped that this report by the Distribution Working Group of the Cement Industry Committee will be used to augment some of the principles outlined, as they apply particularly to cement plants.

This Recommended Practice reflects the thinking of members of the Distribution Working Group, consisting of members from cement plants, machinery manufacturers, electric equipment manufacturers, and cement plant designers and builders.