William E. Brumsickle

Dynamic sag correctors: cost effective industrial power line conditioning

Voltage sags, transients, and momentary interruption of power together constitute 92% of the PQ problems encountered by typical industrial customers. The series-parallel connected dynamic sag corrector (DySC) provides statistically significant protection at greatly reduced cost. The DySC is rated 1.5 kVA 1-phase to 2000 kVA 3-phase and features a patented single stage power conversion circuit with minimal stored energy. A unique circuit allows operation with opened upstream circuit breaker. The paper presents a detailed discussion of DySC operating principles and validation of performance. It also provides conditions under which this new category of product can be applied.

A Distributed Static Series Compensator System for Realizing Active Power Flow Control on Existing Power Lines

Flexible AC transmission systems (FACTS) devices can control power flow in the transmission system to improve asset utilization, relieve congestion, and limit loop flows. High costs and reliability concerns have restricted their use in these applications. The concept of distributed FACTS (D-FACTS) is introduced as a way to remove these barriers. A new device, the distributed static series compensator (DSSC), attaches directly to existing HV or EHV conductors and so does not require HV insulation. It can be manufactured at low cost from conventional industrial-grade components. The DSSC modules are distributed, a few per conductor mile, to achieve the desired power flow control functionality by effectively changing the line reactance. Experimental results from a prototype module are presented, along with examples of the benefits deriving from a system of DSSC devices

A distributed static series compensator system for realizing active power flow control on existing power lines

Flexible AC transmission systems (FACTS) devices can control power flow in the transmission system to improve asset utilization, relieve congestion, and limit loop flows. High costs and reliability concerns have restricted their use in these applications. The concept of distributed FACTS (D-FACTS) is introduced as a way to remove these barriers. A new device, the distributed static series compensator (DSSC), attaches directly to existing HV or EHV conductors and so does not require HV insulation. It can be manufactured at low cost from conventional industrial-grade components. The DSSC modules are distributed, a few per conductor mile, to achieve the desired power flow control functionality by effectively changing the line reactance. Experimental results from a prototype module are presented, along with examples of the benefits deriving from a system of DSSC devices.

A grid information resource for nationwide real-time power monitoring

A significant barrier to improving the power quality at industrial facilities is the lack of contemporaneous and historical power quality and reliability data. A new Web-enabled near-real-time power quality and reliability monitoring system, termed I-Grid, has been developed to provide such information on a nationwide basis. The ultralow-cost sensors record power events and send event data via the Internet to the system database servers using an internal modem. Data display, e-mail event notification, site administration, and summary reporting of the data are achieved via a Web browser. In cooperation with the U.S. Department of Energy, the Electric Power Research Institute, and leading utilities and manufacturers, the deployment of these sensors has begun, with a target deployment of 50 000 monitors across the U.S. and Canada over the next 2-4 years. This paper discusses the implementation of this grid information resource, and discusses data captured by the network since early monitors were deployed in 2001.

Equipment failures caused by power quality disturbances

This paper provides insight into a failure mechanism that impacts a broad range of industrial equipment. Voltage surges have often been blamed for unexplained equipment failure in the field. Extensive voltage monitoring data suggests that voltage sags occur much more frequently than voltage surges, and that current surges that accompany voltage sag recovery may be the actual culprit causing equipment damage. A serious limitation in equipment specification is highlighted, pointing to what is possibly the root-cause for a large percentage of unexplained equipment field failures. This paper also outlines the need for a standard governing the behavior of equipment under voltage sags, and suggests solutions to protect existing equipment in the field.

Reduced switching stress in high-voltage IGBT inverters via a three-level structure

High voltage (3.3-4.5 kV) insulated gate bipolar transistors (HVIGBTs) are limited in SOA and ability to be effectively used in hard switched 2-level PWM inverters. The proposed operation sequence for the well known 3-level inverter allows use of HVIGBTs at near-rated voltage while cutting switching loss in half and allowing 3-level PWM for improved harmonics spectrum. Simulation and laboratory results prove the concept.

Pilot evaluation of electricity-reliability and power-quality monitoring in California's Silicon Valley with the I-Grid(R) system

Power-quality events are of increasing concern for the economy because todays equipment, particularly computers and automated manufacturing devices, is susceptible to these imperceptible voltage changes. A small variation in voltage can cause this equipment to shut down for long periods, resulting in significant business losses. Tiny variations in power quality are difficult to detect except with expensive monitoring equipment used by trained technicians, so many electricity customers are unaware of the role of power-quality events in equipment malfunctioning. This report describes the findings from a pilot study coordinated through the Silicon Valley Manufacturers Group in California to explore the capabilities of I-Grid(R), a new power-quality monitoring system. This system is designed to improve the accessibility of power-quality in formation and to increase understanding of the growing importance of electricity reliability and power quality to the economy. The study used data collected by I-Grid sensors at seven Silicon Valley firms to investigate the impacts of power quality on individual study participants as well as to explore the capabilities of the I-Grid system to detect events on the larger electricity grid by means of correlation of data from the sensors at the different sites. In addition, study participants were interviewed about the value they place on power quality, and their efforts to address electricity-reliability and power-quality problems. Issues were identified that should be taken into consideration in developing a larger, potentially nationwide, network of power-quality sensors.

I-grid TM : infrastructure for nationwide real-time power monitoring

A significant barrier to improving the power quality at industrial facilities is the lack of contemporaneous and historical power quality and reliability data. A new web-enabled near-real-time power quality (PQ) monitoring system, the I-Grid/spl trade/, has been developed to provide such information on a nationwide basis. The ultra-low cost I-Sense/spl trade/ monitors record power events and send event data via the Internet to the I-Grid database servers using an internal modem. Data display, email event notification, site administration and summary reporting of the data is achieved via a web browser. In cooperation with the DOE, EPRI, leading utilities and manufacturers, the deployment of I-Sense monitors has begun, with a target deployment of 50 000 monitors across the US and Canada over the next 24 years. This paper discusses the implementation of the I-Grid system, and discusses data captured by the I-Grid since early monitors were deployed in 2001.

Design considerations for a soft-switched modular 2.4-MVA medium-voltage drive

A new six-phase, 2.4 MVA, soft-switched, medium voltage drive system utilizing series stacked modules with low voltage devices has been developed. The drive system combines a new soft-switched DC-DC converter with resonant DC link inverter technology to deliver extremely low THD sinusoidal output, high power density and high efficiency. The series stacked configuration with the associated single-phase loading lead to unique power and control design challenges. Device selection, control of parasitic elements, sensing methods for converter control, custom magnetic component design and clamping techniques have lead to a substantial improvement in device voltage utilization. The DC-DC converter controls must regulate the intermediate DC bus voltage under single phase loading while balancing transformer excitation and maintaining zero voltage switching, among other tasks. Proper control of the RDCL inverter requires the selection and tuning of the appropriate modulator and understanding its affect on the power circuit ratings.

Operational experience with a nationwide power quality and reliability monitoring system

An end-to-end web-based electric power quality and reliability monitoring system has been operating since mid-2002. Today, more than 700 monitor nodes are placed in 46 states across the nation and more than 90000 PQ events have been captured. Exceptionally low cost monitors are key to affording broad deployment by corporations, utilities, and single customers. Large industrial users benefit from the event notification, data reporting and statistical summary capabilities to understand the impact of power quality on their operations at multiple facilities and to specify optimal solutions to mitigate these problems. Case studies from the first year of system operation are discussed, which demonstrate the potential for realizing a nationwide power quality and reliability monitoring system.