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This paper summarizes the IEEE C37.234–2009 Guide for Protective Relay Applications to Power System Buses. In the Guide, concepts of power bus protection are discussed. Consideration is given to availability and location of breakers, current transformers, and disconnectors as well as bus switching scenarios, and their impact on the selection and application of bus protection. A number of bus protection...
This paper summarizes the IEEE C37.234-2009 Guide for Protective Relay Applications to Power System Buses. In the Guide, concepts of power bus protection are discussed. Consideration is given to availability and location of breakers, current transformers, and disconnectors as well as bus switching scenarios, and their impact on the selection and application of bus protection. A number of bus protection...
High impedance bus differential relays are used on most of the busses in North America. The popularity can be explained by the good performance of this scheme in relation to CT saturation and the low cost, if used on a simple bus system. However with the introduction of numerical relays and their low CT burden as well as their ability of measuring several feeder currents, a low impedance bus differential...
By application of numerical differential protection devices over digital communication links it is possible to transfer, apart from the protection relevant data, additional binary information and measured values. Communication convertors adapt the telegrams of the devices to the communication medium. Apart from classical pilot wire links and optical fibres it is also possible to use modern communication...
The electric power system maintains a dynamic and delicate balance between generation and load in normal operatio condition. A disturbance, such as a sudden change of load, a power system fault, or a trip of a large generation unit, may break the balance, cause the oscillations among the generator rotor angles and force the generators to adjust to a new operating condition. The adjustment will not...
High impedance bus differential relays are used on most of the busses in North America. The popularity can be explained by the good performance of this scheme in relation to CT saturation and the low cost, if used on a simple bus system. However with the introduction of numerical relays and their low CT burden as well as their ability of measuring several feeder currents, a low impedance bus differential...
The electric power system maintains a dynamic and delicate balance between generation and load in normal operation condition. A disturbance, such as a sudden change of load, a power system fault, or a trip of a large generation unit, may break the balance, cause the oscillations among the generator rotor angles and force the generators to adjust to a new operating condition. The adjustment will not...
The MHO characteristic is used very extensively in North America over the last decades in distance relaying. They are simple to design with electro mechanical components and simple to set. With the introduction of static and numerical relays other characteristics have been developed to overcome certain limitations of the MHO circle. More and more quadrilateral characteristics are used here in North...
This paper gives an introduction to the problematic phenomena of arc flashing. For protection engineers important terms and facts in the NFPA 70E standard and the IEEE 1584 standard will be presented. The importance of the fault clearing time will be discussed in detail. Protection schemes which achieve fast fault clearing times for bus faults and feeder faults will be reviewed. In this paper an application...
The new IEC 61850 substation communication standard is almost two years old. Worldwide, there are already over one hundred substations that have been commissioned and running with this new standard. Several projects in North America have been implemented with IEC 61850 by using products from a single manufacturer. This paper will report on the status of a 500 kV project, which is the first multi-vendor...
The new IEC61850 substation communication standard is almost two years old. Worldwide, there are already over one hundred substations that have been commissioned and running with this new standard. Several projects in North America have been implemented with IEC61850 by using products from a single manufacturer. This paper will report on the status of a 500KV project, which is the first multi-vendor...
Fault locator functionality is a standard feature in modern numerical feeder protection devices for transmission systems. It is common practice to calculate the fault location via an impedance measurement separately at each line end. All calculation techniques used to date in this ldquosingle endedrdquo fault location exhibit limited accuracy. The accuracy that can be obtained is limited by natural...
This paper will describe a new algorithm for detecting the out of step and power swing condition. This algorithm, which is based on continuous impedance monitoring, doesn't require a blinder or concentric characteristics. Therefore no settings are needed. The algorithm continuously monitors the speed and the shape of the impedance trajectory and will immediately see the start of a power swing cycle...
Modern numerical relays use improved measuring and stabilizing methods and can therefore tolerate current transformer (CT) saturation to a large extend. Dimensioning of CTs for short time to saturation however requires precise consideration of the transient CT behaviour in the first milliseconds after fault inception. Therefore, traditional calculation and dimensioning guidelines have to be reviewed...
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