AEP System Research Articles

Effect of Resin and Blocked/Unblocked Hardener Mixture on the Production of Epoxy Foams with CO2 Blocked Hardener in Batch Foaming Process.

The present study focuses on the processing and properties of epoxy foams by the use of CO2 blocked hardener N-aminoethylpiperazine (B-AEP) and different resins. Although some studies described the foaming with carbamates, little attention has been given to the interaction of resin properties (such as viscosity) on the foaming performance. Therefore, two resins, diglycidyl ether of bisphenol-A (DGEBA) and epoxy novolac (EN), as well as their 50:50 blend, were foamed with B-AEP and unblocked/blocked AEP hardener mixtures in a batch foaming process. Furthermore, the commercially available chemical blowing agent para-toluenesulfonyl hydrazide (TSH) was used as a benchmark for commonly used chemical blowing agents. The lowest density in this study was reached by the DGEBA+B-AEP system in the range of 215 kg/m3 with the drawback of an inhomogeneous cell structure and high cell size distribution. The best cell morphology and lowest cell size distribution was reached with the EN+15:85% unblocked:blocked hardener mixture, resulting in a density in the range of 394 kg/m3. A syntactic foam was achieved by a DGEBA+50:50% unblocked:blocked hardener mixture with a density of around 496 kg/m3. It was found that a higher viscosity of the resin lead to an increase in the density and a decrease in the cell size distribution range as a result of a closer expansion time window.

The effect of the clicks of an AEP system on the BIS and on levels of consciousness during anaesthesia and sedation

The effect of the clicks of an AEP system on the BIS and on levels of consciousness during anaesthesia and sedation

Improved representation of generator and load dynamics in the study of voltage limited power system operations

The implementation and significance of modeling improvements in operational planning studies of a voltage limited network interface in the AEP System are presented. The modeling improvements are with respect to conventional load flow based modeling and consist of significant elements relevant to system voltage performance documented in the literature. These elements include voltage sensitive dynamic load models; distribution system equivalents that include load tap changer (LTC) regulation of load voltage; generator field current limiting action; and generator voltage regulator reactive line drop compensation. Both dynamic and steady-state aspects of voltage stability performance of the AEP voltage limited network interface are addressed. The implications of conventional load flow modeling in operational planning studies are discussed with reference to the results of the generator and load modeling improvements.

96/00278 Increased utilization of coal combustion byproducts (CCB) and related benefits on the AEP system

96/00278 Increased utilization of coal combustion byproducts (CCB) and related benefits on the AEP system

Voltage transformer ferroresonance from an energy transfer standpoint

A novel approach to determine whether ferroresonance can occur is developed. It is based on the energy transferred from the system to the voltage transformer during the switching transient. This approach is used to develop a practical test criterion to indicate if ferroresonance can occur at a specific station. The numerical values of the parameters used in this criteria can be easily determined for any station. The analytical results are compared with experimental data gathered at three stations on the AEP system with good agreement.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Voltage Transformer Ferroresonance from an Energy Transfer Standpoint

A novel approach to determine whether ferroresonance can occur is developed. It is based on the energy transferred from the system to the voltage transformer during the switching transient. This approach is used to develop a practical test criterion to indicate if ferroresonance can occur at a specific station. The numerical values of the parameters used in this criteria can be easily determined for any station. The analytical results are compared with experimental data gathered at three stations on the AEP system with good agreement. >

In-Service Availability of the AEP System Control Center

The development period availability expectations for the AEP System Control Center (SCC) are contrasted with the first two years of operational experience. The reasons for in-service unavailability are presented and discussed. Recommendations are made relative to the inclusion of new factors into procurement phase availability calculations and acceptance tests.

In Service Availability of the AEP System Control Center

The development period availability expectations for the AEP System Control Center (SCC) are contrasted with the first two years of operational experience. The reasons for in-service unavailability are presented and discussed. Recommendations are made relative to the inclusion of new factors into procurement phase availability calculations and acceptance tests.

Quadratic Loss Formula For Reactive Dispatch

A loss formula based on the incremental power flow being a reduced form of the power flow is derived. The algorithm for its determination which utilizes the Jacobian matrix is given and the properties of the coefficients characterizing the incremental power flow are discussed. The key concept is the determination of a quadratic form such that second derivatives of the incremental power flow and of the load flow variables agree. The concept lends itself to load flow optimization, in particular for reactive dispatch for which an example (118 bus AEP system) is discussed. The results prove the expected high performance.

A New Measurement Technique for Tracking Voltage Phasors, Local System Frequency, and Rate of Change of Frequency

With the advent of Substation Computer Systems dedicated to protection, control and data logging functions in a Substation, it becomes possible to develop new applications which can utilize the processing power available within the substation. The microcomputer based Symmetrical Component Distance Relay (SCDR) described in the references cited at the end of this paper possesses certain characteristics which facilitate real-time monitoring of positive sequence voltage phasor at the local power system bus. With a regression analysis the frequency and rate-of-change of frequency at the bus can also be determined from the positive sequence voltage phase angle. This paper describes the theoretical basis of these computations and describes results of experiments performed in the AEP power system simulation laboratory. Plans for future field tests on the AEP system are also outlined.

American-Electric Power System Electric Thermal Storage Program: An Evaluation of the Impact on the Gereration System

The impact of the cperation of Electric Thermal Storage (ETS) equipment o a residential customr's daily load shape, based on test data, was estimated. The effect on the system's load shape was then determined, and an evaluation of econormic benefits resulting frcm this change performed, both from the standpoint of an individual ETS installation and a hypothetical expansion of installations. Incentives required to implement sach a program wre considered, and costs of such incentives compared with expected benefits. Finally, the rumber of ETS installations which the AEP System could accommodate was considered, to assess the feasibility of a potential ETS implementation program.

American Electric Power System Electric Thermal Storage Program: An Evaluation of the Impact on the Generation System

The impact of the cperation of Electric Thermal Storage (ETS) equipment o a residential customr's daily load shape, based on test data, was estimated. The effect on the system's load shape was then determined, and an evaluation of econormic benefits resulting frcm this change performed, both from the standpoint of an individual ETS installation and a hypothetical expansion of installations. Incentives required to implement sach a program wre considered, and costs of such incentives compared with expected benefits. Finally, the rumber of ETS installations which the AEP System could accommodate was considered, to assess the feasibility of a potential ETS implementation program.

Real Time Results with On-Line Network Equivalents for Control Center Applications

Extensive analysis and testing with real time data of the AEP system for various types of equivalencing techniques has been performed. It was found that for real time on-line applications the REI-type equivalents performed better than other equivalencing methods (Ward-type equivalents). It is shown that the equivalent updating procedure used for REI-type equivalents cannot be used for Ward-type equivalents. Ward-type equivalents which performed well for off-line planning applications and for some simulated real time applications did not work as well under realistic on-line conditions.

Power Engineering Society 1981 Prize Paper Real-Time External System Equivalent for on-Line Contingency Analysis

An equivalent model for external systems to be used in on-line contingency studies is presented. The equivalent uses Dimo's REI network reduction technique together with a method for tracking on-line injection and network changes in the external system by modifying the parameters of the equivalent. This important characteristic results in a dependable equivalent with excellent response at all operating points. Another important aspect of this paper is the fact that for the first time the testing of on-line equivalents is carried out in a real-time environment rather than under simulated conditions. The response of the equivalent model proposed herein to the outage of a major 765KV circuit in the AEP System is reported and the results provided by the equivalent are compared to the results provided by the AEP State Estimator. The results obtained with the model presented in this paper are superior to the results obtained with other equivalent models.

A Microcomputer Based Ultra-High-Speed Dostance Relay: Field Tests

This paper describes the field tests of a microcomputer based Symmetrical Component Distance Relay (SCDR). A brief review of the relay operating principle is followed by a description of the field tests conducted by staging faults on a 765 kV transmission line on the AEP system. Performance of SCDR during these tests is analyzed. A newly developed Ultra-High-Speed (UHS) mode of operation for the SCDR is presented, and the performance of the relay in the Ultra-High-Speed mode is illustrated with the data gathered during the field tests.

Discriminating Acceleration Limiting Devices for Turbine Generators

This paper presents a discussion of the need for and the development of a discriminating acceleration limiting device. Such a device was required to be incorporated into the control of the Brown Boveri Corporation 1300 MW turbine generators operating on the American Electric Power System. This acceleration limiting device must be capable of discriminating between temporary acceleration caused by a system disturbance and sustained acceleration due to significant load rejection. The need for developing such a device for the Brown Boveri turbine generators was made apparent by an event which occured on August 28, 1974 and resulted in a loss to the AEP System of almost 2600 MW.

Biochemical polymorphisms in muscle and liver extracts and in the serum of the rainbow trout Salmo gairdneri

SummaryThe frequency of polymorphic phenotypes determined by starch gel electrophoresis from six enzyme systems was investigated on 664 rainbow trout (stock I) originating equally from six full‐sib families. The enzyme systems studied were CA, AKP, G‐6‐PD, SOD, AEP, and 6‐PGD.On material deriving from six parental matings totalling 212 offspring (stock II) the mode of inheritance of the first four enzymes (AEP and 6‐PGD were not polymorphic) and the additional systems IDH, PGM, Alb, and Psta, not analysed in stock I, were investigated.The G‐6‐PD system showed no polymorphism in the family material. The CA, PGM, Alb, and Psta systems were easily identifiable. Their mode of inheritance with two alleles each can be considered as proven. For SOD three alleles, in four out of six possible progeny types, were found, for which the postulated mode of inheritance was confirmed.For IDH the mode of inheritance found by Allendorff &amp; Utter (1973) was confirmed. This pattern shows two disomic gene loci, one of which is monomorphic, while the other carries four different alleles.The number of alleles and their mode of inheritance for the AEP system, which was not clearly identifiable, could not be elucidated.

Experience with part-winding resonance in EHV auto-transformers: Diagnosis and corrective measures

Four failures of large EHV auto-transformers on the AEP system are described. The failures were initiated by flashovers in the no-load tap changer during system faults. Investigations and tests attribute the flashovers to part-winding resonance. Test data is presented for various terminal conditions and wave shapes corresponding to system transient conditions. The relationship of these tests to ANSI standard dielectric tests is discussed. Corrective measures for existing transformers include arresters tied to an internal crossover connection and capacitor banks connected to the delta tertiary windings.

Stochastic load flows

The load flow study has been at the center of studies made for designing and operating power systems for many years. It is well known that forecasted data used in load flow studies contain errors that affect the solution, as can be evidenced by running many cases perturbing the input data. This paper presents a method for calculating the effect of the propagation of data inaccuracies through the load flow calculations, thus obtaining a range of values for each output quantity that, to a high degree of probability, encloses the operating conditions of the system. The method is efficient and can be added to any existing load flow program. Results of cases run on the AEP system are included.

A New Shunt Reactor Principle Proved: Designed Data and Factory Test Results for Units Built on The Insulated Core Principle

Effective control of electrostatic as well as electromagnetic field distribution within EHV transformer-type equipments significantly enhances their on-line performance. This paper describes the first application of the insulated core principle for management of fields of a 765 kv shunt reactor installed on the AEP System. Design techniques and ta are presented and the modular concept of reactor construction in an oil-filled device is described. Results of feasibility studies of reactors for future UHV systems are included.