This paper concerns itself with the utilization and the coordination of reactive sources and other voltage control equipment in system operations. The reactive sources specifically considered are: generators, synchronous condensers, switched static capacitors and shunt reactors, and transformers with and without load tap changing capabilities. The paper presents a methodology for determining the benefits that can be achieved in the proper scheduling of these sources in a power system. The benefits as shown are: savings in fuel production costs, unloading of the system equipment, improved system security, and improved voltages over the system. From a large system study conducted, it appears that these benefits can be obtained with only minor modifications in present scheduling procedures.

Benefits of Voltage Scheduling in Power Systems

The ability to calculate the dynamic stability limits of synchronous machines is of increasing importance today as generation and transmission equipment are being applied with higher reactances and correspondingly lower stability margins. This paper describes a digital computer program which enables the rapid computation of dynamic stability limits for a single machine connected to an infinite receiving system through a transmission line. Effects of excitation and prime mover power controls are included making the program a valuable tool for the equipment designer. Typical results illustrate the effect of terminal voltage, transmission line reactance, and machine inertia on the stability limits. The concept of damping ratio as an index to relative stability is discussed and illustrated. Also shown are the effects of neglecting saturation and other second-order effects on the calculation of dynamic stability.

A Digital Computer Program for the Automatic Determination of Dynamic Stability Limits

Underexcited Reactive Ampere Limit for Modern Amplidyne Voltage Regulator [includes discussion]

Field Excitation in Relation to Machine and System Operation [includes discussion]

This paper presents a brief review of the coordination issues between Under Excitation Limiters (UELs), Loss of Excitation Relays (LOEs) and generator capability. The generator's capability limitations in the leading power factor region are discussed. Present industry practice and some common alternatives of LOE settings are reviewed. The settings of the UEL are reviewed in this context.

Coordination of under excitation limiters and loss of excitation relays with generator capability

1. A method has been developed whereby the optimum configuration and conductor area may be determined for a given EHV transmission line, taking into account all the parameters which have economic significance. 2. This method is general, and applicable to a wide range of system configurations, transmission distances, voltages, and loadings per circuit. Economic evalution factors may be varied to agree with available cost data, and the judgment and policies of the utility management. 3. This method is embodied into a digital computer program for the IBM705 computer, providing rapid computation of any case to be investigated. 4. Fifty-eight different cases were investigated in this study, to determine the effect of varying the system parameters and the economic evaluation factors over a wide range of values which are of practical interest for the United States and Canada. 5. Annual cost differentials between the minimum cost points for the various configurations are considerable and correspond to several per cent of the annual charges on the line investment. 6. The optimum configuration depends upon the particular values of the system parameters and economic evaluation factors. Therefore it is difficult to draw over-all conclusions, valid for all cases. Rather, each specific case will have to be investigated separately according to the method described in this paper. 7. In general, as the load per circuit increases, relative to surge impedance loading, the number of conductors per phase corresponding to the optimum configuration also increases. 8.

Economics of Single and Bundle Conductors for Extra-High-Voltage Transmission

STEADY-STATE OR TRANSIENT STABILITY problems are not significant limitations on most power systems today. However, under some circumstances it is logical to split existing systems and perhaps add reactors to prevent costly increases in interrupting capacity of circuit breakers. It has become apparent recently that transient stability problems can readily develop if this approach is carried too far.

System stability limitations and generator loading

System Stability Limitations and Generator Loading [includes discussion]

THE USE of bundle conductors for power transmission was first proposed by P. H. Thomas in 1909. The electrical characteristics of bundle conductors were then recognized to be superior in many respects to the characteristics of comparable single conductors. However, it was also known at that time that bundle conductors had higher initial costs and a more complex mechanical structure than single conductors. Therefore, no significant applications of this new concept were made in the next 40 years, although in 1931 C. A. Boddie proposed a 500-kv line with four conductors in a bundle. As a result of extensive investigations made in the last 10 years of the electrical and mechanical characteristics of bundle conductors, many transmission lines have been and are being built all over the world utilizing this type of construction.

H. O. Simmons

Papers

Economics of Single and Bundle Conductors for Extra-High-Voltage Transmission

System stability limitations and generator loading

System Stability Limitations and Generator Loading [includes discussion]

Conductor economics for EHV transmission