Jakov Vico

High impedance fault detection on rural electric distribution systems

A high impedance fault (HIF) results when an energized primary conductor comes in contact with a quasi-insulating object such as a tree, structure or equipment, or falls to the ground. The significance of these previously undetectable faults is that they represent a serious public safety hazard as well as a risk of arcing ignition of fires.

Application of peer-to-peer communication, for protection and control, at Seward distribution substation

This paper discusses application of high-speed peer-to-peer communication over local area network (LAN) as a tool that helps Cinergy to achieve reduction in installation, commissioning, upgrade, maintenance and operation costs. Exchange of UCA Generic object oriented substation event (GOOSE) messages between relays connected to the LAN is successfully used for the breaker failure, accelerated protection of the distribution bus, transformer protection lockout feature, GOOSE testing, substation interlocking and blocking. Also, this system of exchange of the messages over LAN provides significant advantage for the future expansion of the distribution substation, as well as easy integration into automatic throw over scheme. The three relays types are used for the advanced feeder protection, transformer protection, and control of the high voltage (HV) switches. All relays have pushbuttons on the front (faceplate) for easy control and testing of substation equipment. Relays pushbuttons, light emitting diodes (LEDs) and nonvolatile latches also reduced cost for hardware, wiring, design, testing and commissioning. This application meets Cinergy Distribution Standard in a very cost effective way, with great benefits of integration, as there is no need for additional hardware (protocol converters) or additional software. It provides an efficient way of local/remote metering, control, monitoring, recording, communication and protection functions.

IEC61850 protocol - practical applications in industrial facilities

A new standard, defining protocols has been evolving since 1997, called IEC61850. This standard enables several industrial benefits when using an Ethernet network, such as high speed device-to-device communications (i.e. peer-to-peer communications both digital and analog values) within cycles and between different vendors, high-speed processing of analog signals and a common database naming format and structure. This paper will review the fundamentals of IEC61850 protocol including network requirements. It will also discuss three practical applications of IEC61850 protocol such as zone interlocking protection scheme, main-tie-main bus transfer scheme and load shedding scheme. Bus zone interlocking scheme, is an efficient application of IEC61850 GOOSE messaging. In this scheme, the main relay will use definite time overcurrent element and the feeder relay will use time overcurrent element. The main relay selectively is allowed to trip or block depending on location of faults as identified from feeder relays. Main-Tie-Main bus transfer is a common application in industrial facilities. Voltage Main-Tie-Main bus transfer is a very common transfer scheme within industrial facilities. Main-tie-main automatic bus transfer can be applied using two protective relays and IEC61850 GOOSE messaging. A fast load shedding (FLS) scheme rapidly sheds load in a large industrial facility in response to loss of one or more incoming sources in order to avoid complete system collapse while maintaining supply to as much of the process as practical. Unlike undervoltage, underfrequency, or rate of frequency decay load shedding schemes, the fast load shedding scheme can initiate load shedding before the system frequency/voltage declines, which in many cases is essential for maintaining system stability. The fast load shed scheme uses IEC61850 GOOSE communications to collect load and incoming source power information from a very large number of end units at very high speed.

Advanced distribution reclosing using wireless communications

A key smart grid solution that affects quality of electric service to rural electric cooperative customers is automatic distribution reclosing. Distribution reclosers offer rural electric cooperatives the benefit of isolating faults and minimizing the number of effected customers during a fault condition. Over the years, sequence coordination between upstream and downstream reclosers has for trip coordination. This paper will discuss using recloser controls with Ethernet communications and 900Mhz Ethernet radios to efficiently communicate to each other using peer-to-peer communications. Smart trip coordination and fault isolation will be discussed using this available communication technology.

Principles in Motor Protection

This article discusses the fundamentals of motor protection principle. A brief overview of the existing protection philosophy for asynchronous motors is reviewed with a special consideration of thermal protection of motors. Because large synchronous motors are used in the cement industry, a review of additional functions required for protection and control of synchronous motors is given.

Improving the usage of temperature sensors for motor thermal protection

This paper presents different aspects of using temperature sensors as a part of the motor thermal model. Different types of sensors, mostly used on medium voltage machines, are presented. The most common solutions of building sensors into motor windings are described. The differences between induction and synchronous motors are discussed regarding the benefits of temperature sensor usage. It is considered how a sensors accuracy and time response can influence the efficiency of thermal motor protection. The basics of a typical temperature biasing algorithm are explained. A few modifications of the commonly used biasing methods are proposed. An option of comparing the calculated thermal capacity used with sensor readouts in the case of longer constant motor load conditions is discussed.

Protection and control of low voltage motors used in industrial applications

As low voltage motors are critical assets in todays industrial applications this paper will review the applications of microprocessor-based protection and control on low voltage motors less than 600 V AC in industrial facilities. It will review principles of low voltage motor protection (thermal overload, ground fault, unbalance, etc.). In addition, the paper will discuss the starting control of low voltage motors and review the different starting types (Full Voltage Non-Reversing, Full Voltage Reversing, Two Speed, Wye-Delta, Inverter, Soft Starter). Communications play a key role in the starting and stopping of low voltage motors. This paper will also discuss several different starting/stopping controls using communication protocols, such as Profibus, DeviceNet and Modbus.

Motor Protection Principles

This paper discusses the fundamentals of motor protection principles. Every motor is designed for a specific operating temperature depending upon its insulation. Once this limit is exceeded its life decreases drastically. Over heating condition may arise due to several factors like supply system disturbance, electrical unbalance conditions, faults, load variation and environment. It is essential to have a proper coordination between development of protection principles and the design of motors to understand the concept of motor heating and how thermal protection for motors can be used to prevent loss of motor life. In this paper an overview of existing protection methods for motors is reviewed with a special consideration of thermal protection of motors.

Reducing Outages Through Improved Protection, Monitoring, Diagnostics, and Autorestoration in Transmission Substations—(69 kV and Above)

This paper primarily addresses the subject of reducing outages or reducing the outage duration, auto-restoration applications for transmission substations, (where “transmission” is defined as 69 kV and higher), and the subject of proactively preventing outages. This paper is a summary of the report of K3-WG for transmission systems. The contribution of this paper includes the presentation of the state-of-the-art, practical techniques and measures for preventing and reducing outages in transmission substations which, if properly adopted, can significantly improve transmission system reliability.

Effect of Distribution Automation on Protective Relaying

Distribution Automation (DA) is part of todays evolution of the distribution system. Many utilities already have some Distribution Automation applications (e.g., remote controlling of feeder switches and breakers, automatic reconfiguration, fault detection, fault location, voltage and reactive power control, Advanced Metering Infrastructure (AMI), etc.) and the trend is undeniable and expanding.