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In this paper attention is focused on a power pool coordinating center which monitors the line flows but lacks detailed information on pool member topology and operation. A disturbance in an area of the power pool is sensed by tie line flows. The paper uses the BPM (Biproportional Matrix) algorithm with a non-linear gradient projection method and optimal aggregate/disaggregate rules for determining the optimal tie line flows to be assigned to the reconfigured network N+6N, where N is the original power system network in each area. This is an excellent measurement technique for the line contingency problems and provides an efficient tool for power pool dispatch center operator actions.

During the past ten years a number of authors have put forward techniques for tuning power system stabilizers (PSS) in the literature. Some of these techniques have been tested in on-site applications and others have been evaluated using simulation techniques. This paper describes a theoretical basis, and supporting experimental evidence from tests performed at a power plant, for tuning power system stabilizers using frequency response techniques. By using the method described in this paper, the power system analyst is able to obtain an approximate measure of the amount of damping that can be expected from the stabilizer in damping out tie- line power oscillations. The tests were conducted on the inter- tie between the Alberta and British Columbia Hydro power pools. Test results indicated a direct correlation between the improvement in the electric power damping as observed by field tests and that predicted by theoretical means. Although the method suggested in this paper has general application to power system stabilization for local mode damping and inter- tie damping it was applied to the specific case where the tie- line power was used as a feedback signal to the stabilizer.

This paper develops the methodology, based on the segmentation method, to evaluate the production costs of two interconnected systems. The demand plane is divided into a grid structure, or segments, of equal size. Each segment contains the joint probability of the load in the range of the selected segment as well as the first moments of load, or equivalent load, and residual tie line capacity for each system. The methodology proposed is accurate and computationally efficient. The method is applied to the evaluation of expected energy generation, unserved energy as well as production costs of two interconnected systems. The results also compared to those utiliz Expansion.

In many situations of power system restoration or emergency control load flow, often dynamic load flow, results are needed at a time scale which makes regular load flow computations impractical. In this paper a low order dynamic model is introduced which retains fully detailed and precise representation of the critical components (such as strong backbone lines like EHV or weak tie lines) where the interest is focused and reduces the detail of representation of other parts of the system gradually with their distance from the spotlighted sections where details are needed. The result is a low order and hence very fast computation with not only detailed but also quite precise results for those parts of the system which are critical. This approach is very flexible, it can be used to compute tie line load and frequency swings on an interconnection of areas or static loads on the tie lines of such a system affecting third parties in a power trading situation. It can be used to compute precisely and fast the EHV system loads or any combinations of such elements. The operator is quite free to choose what should be represented in precise detail.

The Dispatched Control principle is developed to assure on line economic production of power including losses while maintaining system wide frequency and tie line load setpoints as well as the AC and, if present, the DC voltage profiles. New feasible algorithms are introduced for the reactive power and multiterminal DC system controls. Previously published papers [1], [2] have treated the reevaluation of the Dispatched Control of real power generation or AGC. It is advocated here to treat system security not on line but as part of unit commitment combined with on line active emergency control. A new "Transjection Model" for the compound multiterminal HV-AC-DC system is introduced which emphasizes structural properties of such systems and is instrumental in developing a system wide, uniformly structured Dispatched Control.

An automatic static compensator shunt connected at the synchronous generator terminals using an appropriate control strategy is shown to yield superior dynamic stability limits than that of a conventional or a dual excited machine. The control signal to actuate the static compensator is derived from a comparison of the reactive power flow on the tie line and that produced by the compensator. A state spacs mathematical model for the proposed system is formulated and the dynamic stability limits for various studies are obtained using sigenvalue technique.

The paper presents a Hybrid-computer simulation study of the damping effectiveness of static phase shifters. Control strategies based on tie line power and/or frequency deviations feedback, and utilizing fast acting static phase shifters to modulate tie line power flow are effective in damping power and frequency excursions. Implementing static phase shifters as a stability enhancement technique could improve dynamic stability and, hence, increase tie line power capacity.

This paper extends the basic techniques used for considering the uncertainty associated with the system parameters of a single area system to two interconnected systems and presents an approximate method for evaluating the effects of these uncertainties on the LOLE of two interconnected systems. The effect of uncertainty in tie line parameters on the LOLE index is examined. Equations are derived for calculating the mean and variance of the LOLE in each system under the different uncertainties. The methods are compared by application to a hypothetical system and to the IEEE Reliability Test System.

Cost analysis is an important aspect in system planning whether the system is interconnected with other systems or the system is meeting its own demand. nd. A probabilistic technique for the calculation of production cost of two interconnected systems with correlated elated demands is developed. The proposed method is based on the notion of statistical cumulants and the bivariate Gram-Charlier expansion. The method is computationally utationally efficient since convolutions are performed using the appropriate statistical cumulants. The method hod has been applied to two interconnected systems in which the production costs for each system are evaluated ed for different tie line capacities.

Nathan Cohn's newly proposed technique of coordinated, system-wide correction of time error and inadvertent interchange is examined and validated by computer simulations. Area and system performances are investigated for a sudden change in load or generation in a three-area power system. The following effects are examined: changing the time of correction; simultaneous versus individual correction of time error and inadvertent interchange; the type of disturbance; the governor delay time; and the presence of sustained errors.

There has been a considerable amount of work done in the area of static capacity reliability evaluation in interconnected systems. The first important paper in this subject1 utilized a two dimensional probability array upon which the tie line constraints were imposed. The basic generating unit statistics in static and spinning reserve studies are fundamentally different and in the latter case the problem is a question of will the capacity immediately available to the system be capable of satisfying the load in the event of possible capacity and load changes. The possible assistance under these conditions from an interconnected system cannot therefore be neglected in determining the risk of just carrying or failing to carry the system load. In a static capacity interconnected system study, the tie line is normally rated at its nominal value. In a spinning study, the tie line rating or inter-system transfer capability will depend upon the immediate and known conditions between each system, i. e., the existing transmission configuration, the scheduled generation pattern, etc. etc. These could be quite variable even over the course of a day.

The 6-stand hot strip finishing mill planned by Algoma Steel would impose frequent swings on the utility tie line of 41 MW and 41 Mvar. Each swing would occur over a 10-second interval. To avoid these swings on the utility tie, a steam power plant rated 25 MW continuous with features permitting peak cyclic loading to 41 MW and 41 Mvar was installed. Special megawatt and megavar controls vary the power plant output to match the varying input to the strip mill. High-speed recordings of plant performance during strip mill operation are included. This is believed to be one of the few, if not the only, steam power plants operating in this manner.

The second method of Liapunov is used to investigate the optimum settings of certain governor and voltage regulator parameters of interconnected hydro-electric generating sets. The paper considers a 2-machine system with a simplified tie line representation, and a one-machine system including a detailed model of the generator and its interconnection to an infinite bus.

This paper presents a method of modeling the ties and lines in a power pool for use in dispatch, pool costing, and security- related functions. External pool ties, as well as ties and lines, within the pool are modeled. The networks of all pool members as well as those external to the pool are incorporated in the model. The model consists of a matrix whose rows represent ties and lines and whose columns represent generators, loads if explicitly represented, and net interchanges. Both current and power models are given. The current model yields tie currents when postmultiplied by a current vector and the power model yields tie powers when postmultiplied by a power vector. The model allows loads to be treated explicitly, as mentioned above or implicitly, where the load currents or powers are not required for tie flow determinations. Lines within the areas of the pool are included under the tie designation. Off-nominal autotransformers and phase shifters, which represent a difficult case, are rigorously considered.

A power system stabilizer specifically designed to the performance specifications of various utilities in the Western United States has been developed. The stabilizer utilizes synchronous machine terminal frequency as input. With this input signal, the stabilizing signal is derived using all static components and susceptibility to electrical noise is reduced. The design is modular with the sensing and signal conditioning elements implemented with all solid-state circuitry contained on draw-out printed circuit card assemblies. The design provides independent adjustment of gain and time constants with calibrated controls to allow direct settings from calculated data. Factory tests on the prototype verified its dynamic characteristics met or exceeded performance specifications. Field tests on a 422 MVA unit demonstrated improved damping of oscillations following switching of a tie line.