Abstract In oil and gas production, the multiphase flow rate is one of the most important measurements at the wellhead because it is essential for production allocation, flow assurance, and production surveillance. Multiphase flowmeter devices (MPFM) provide accurate measurements. However, this performance comes at high capital and operating costs that are not economically viable for all wells within aging or on mature fields. A real-time platform based on current technologies offers methods to deploy and automatically update the reduced-order models (ROM) to edge field devices. This approach is used specifically to provide a solution to estimate flow rates in real time at the field level, with and accuracy performance close to what the MPFM delivers, but at a reduced capital and operating costs. Edge field devices can provide the required computing power to run data-driven ROM models on the field side using neural network algorithms, trained to calculate well multiphase flow rate with acceptable accuracy. Periodic updates are performed on the data-driven models on the cloud, and the updated models are downloaded to the edge field device. In this way, the models based on neural networks, deployed and running at the edge field device level, are automatically adapted to changes of the well flow regime over the well's life cycle. An auto-trainable, machine-learning-based, multiphase estimated flow metering system running at the wellsite has been deployed and implemented. The system uses real-time and well test data, mathematical well models, neural-network-based data-driven models, which are automatically trained and updated on the cloud. The solution includes implementation in a real-time digital oil field automation system, which provides the technology platform required by this virtual flow metering system. The system offers a cost-effective way to obtain well flow rate measurement estimates with an acceptable accuracy. This virtual metering system can be used on hundreds or thousands of oil wells simultaneously using real-time data. The system provides oil and gas operators with good real-time flow metering estimates of their wells, accurate enough for production surveillance and allocation.

Electrical field and partial discharge (PD, corona) considerations usually are not in the foreground with low voltage switch- and control gear as per the product standards of IEC, UL and CSA. The design is mainly based on creepage and clearance dimensions, material categories described through CTI and RTI values. IEC product standards refer to the subject of insulation coordination as per the horizontal IEC 60664-family in their normative references. These standards, in principle, require PD measurements for rated voltages exceeding 500 VAC at room temperature. IEC 60664-2 gives some rules for consideration and electrical dimensioning of solid insulation. Miniaturization accompanied by increased power density and raised operational voltage as well as (non-sinusoidal) power supply generated by pulse width modulated (PWM) converters require to reconsider the relevance of electrical field stress in low voltage equipment. With variable frequency drive (VFD) fed motors reflected voltage waves were observed, causing partial discharge effects and insulation damages. Meanwhile motors and cables are available as VFD-proof versions. PD measurements on commercial manual motor controllers with sinusoidal voltages at both room temperature and a more severe elevated temperature related to the maximal operational temperature of the internal components (bimetal trip units) are presented. Conclusions are drawn and recommendations for future designs and testing are proposed.

Motor Protection Circuit Breakers (MPCB) are used in multi motor applications with Variable Frequency Drives (VFD). Devices positioned load side of a drive failed after only several months through thermal degradation. Investigations showed that MPCBs rated lower than 10 A suffer most. Similar designs of different brands were compared and showed in principle the same behaviour. Steep slopes of the DC voltage pulses in combination with the surge impedance of the motor and MPCB are responsible for excessive heat generation in the switchgear destroying the short circuit protection function. Similar effects are known in motors directly connected to drives with cables when exceeding a critical length above which reflected voltage waves occur. It is shown that chopping frequencies should not exceed 4 kHz and critical wire lengths of about 20 m should be respected to avoid damage.

Integrated ship system control is a challenging domain as it involves a set of highly complex and interdependent systems, including electrical power, electric drive propulsion, high-energy weapon systems, various auxiliary systems, and an underlying communications network. Many of the high-level system management questions demanding answers for the electric ship power system and ship service are directly related to control system architecture. As we move toward more decentralized, hierarchical systems, much work remains to be done to optimally determine the appropriate level of control and intelligence at each tier of the architecture. The body of knowledge in this area is limited with respect to power systems and is only slightly more developed for ship service systems. There is a significant need not only to address methods and algorithms from the standpoint of pure decentralization but also to address ways to migrate these methods into an actual distributed, fault-tolerant supervisory control structure that meets the requirements for implementation on the electric ship.

The quality of thermal simulation results depends on the accuracy of both the modelled heat sources and heat sinks. Starting from an existing simplified thermal simulation model, This work describes further steps towards a more accurate representation of the heat sinks in a circuit breaker. Heat generated in switchgear can leave the system either along the metallic conducting path to the connecting wires or through the case to the surrounding air. The former simulation model accurately represented the heat generation and the thermal path along the metallic conductor. However, the path through the case was only summarized by convection coefficients on the metallic parts' surfaces. Due to the high performance requirements of modern breakers it is interesting to know not only the temperatures of the conducting parts but also the thermal impact on the plastic components supporting the conductors or providing essential functions. Therefore, the non-metallic parts of the circuit breaker (including the air within the device) are now part of the model. Consequently, the heat flux through the housing is a result of the simulation and not an estimated boundary condition any more. Moreover, conclusions can be drawn about the thermal stress of the plastic parts of the breaker.

High-power pulsewidth-modulated inverters for medium-voltage applications operate at switching frequencies below 1 kHz to keep the dynamic losses of the power devices at a permitted level. Also, the sampling rate of the digital signal processing system is then low, which introduces considerable signal delays. These have adverse effects on the dynamics of the current control system and introduce undesired cross coupling between the current components i/sub d/ and i/sub q/. To overcome this problem, complex state variables are used to derive more accurate models of the machine and the inverter. From these, a novel current controller structure employing single-complex zeros is synthesized. Experimental results demonstrate that high dynamic performance and zero cross coupling is achieved even at very low switching frequency.

In development of low voltage switchgear, proper thermal design becomes more and more important to provide safe function and reliability in spite of miniaturization and increasing performance demanded of modern devices. Due to the high complexity of heat generation and loss processes it is not easy to predict the thermal behavior of devices under various load conditions, i.e., usually numerous tests are required. Rockwell Automation has started thermal simulations of contactors some time ago, and now is working on a three-dimensional (3-D) thermal model of a manual motor controller. This paper describes how to transform well known contact physics into an application oriented thermal simulation. Linking relations of mechanical engineering with contact physics, the influence of the applied tightening torque at the field wiring terminals on the thermal behavior of the device is considered, as well as the modeling of the contact area, taking into account switching arcs during breaking of various load currents. The simulation results are compared with infrared (IR) pictures and thermocouple measurements of existing devices to validate the theory and furthermore reflect its quality.

This article reviews investigations into reduced bearing life due to voltage source adjustable speed drive (ASD) AC motor operation. Relevant bearing failure mechanisms and indicators are discussed. dv/dt and electric discharge machining (EDM) contributions are discussed and experimental data presented showing the voltage levels on motor shafts when operating with ASDs. Finally, techniques to reduce shaft voltage are discussed, along with the electrical characteristics and interaction of system components. The example chosen is electrostatic shielded induction motors.