Transformers work on the principle of mutual induction to change alternating current voltages from one level to another. They have two coils, a primary and secondary, wound around a ferromagnetic core. When an alternating current flows through the primary coil, it generates a changing magnetic field that induces a voltage in the secondary coil. The ratio of turns between the coils determines the ratio of voltages. Transformers are used widely in power transmission to increase voltages for efficient transfer and then step voltages down for safe distribution and usage. They experience losses from resistance in the coils and hysteresis and eddy currents in the core.
This document discusses transformer protection. It explains that protection is needed to minimize damage, prevent electric failure, reduce outages and costs. The document categorizes different types of transformer faults and classifications of protection functions. It describes differential protection, restricted earth fault protection, overflux protection and other monitoring systems like Buchholz relays, oil temperature indicators, pressure releases and air cell protectors. The document emphasizes the importance of protecting transformers from internal faults and abnormal operating conditions.
This document presents information about Buchholz relays. It discusses that Buchholz relays were first developed in 1921 and are installed in large power transformers to protect against internal faults. The relay contains an upper element that closes an alarm circuit during slow developing faults and a lower element that trips the circuit breaker during severe faults. It operates by detecting hydrogen gas generated from transformer oil decomposition during faults, with the gas causing floats that activate mercury switches to signal alarms or trip the transformer. Buchholz relays provide simple and effective protection for oil-immersed transformers while also detecting slow developing faults earlier than other methods.
The document discusses the Buchholz relay, which is a protective device used in oil-immersed transformers. It contains three elements: an upper float, lower element, and main element containing gas release pockets. It operates based on mechanical phenomena to detect minor faults through gas accumulation or major faults indicated by a surge of oil. The Buchholz relay alerts to faults and can isolate the transformer to prevent accidents, while also allowing analysis of fault gases. However, it only protects below the oil level and has some time delay.
Transformers are static devices, totally enclosed and generally oil immersed. Therefore, chances of faults occurring on them are very rare. But when fault occurring , It is very harmful for power system and our environment. So there are many protection system keep in back-up protection of power system safety.
This document describes various protection schemes for transformers, including differential, restricted earth fault, overcurrent, and thermal protection.
1) Differential protection compares currents entering and leaving the transformer zone to detect internal faults. It provides the best protection for internal faults.
2) Restricted earth fault protection is used to detect high-resistance winding-to-core faults not detectable by differential relays. It uses a neutral current transformer and is sensitive to internal earth faults.
3) Overcurrent protection uses relays with current coils to detect overloads and faults above a pickup threshold. It also includes ground-fault protection.
This document provides an overview of relays. It begins with an introduction to Minda Furukawa Electric Pvt. Ltd, a joint venture company that produces wiring harnesses and relay components. It then defines relays as switches that open and close circuits electromechanically or electronically to control one circuit by another. The document outlines the basic design of relays including their electromagnet, armature and contacts. It describes the main types of relays as electromechanical or solid state. Applications of relays include amplifying signals, isolating faults, and time delay functions. Advantages are their ability to control high voltage circuits with low signals and provide safety. A brief history of relays dates them back
Transformers work on the principle of mutual induction to change alternating current voltages from one level to another. They have two coils, a primary and secondary, wound around a ferromagnetic core. When an alternating current flows through the primary coil, it generates a changing magnetic field that induces a voltage in the secondary coil. The ratio of turns between the coils determines the ratio of voltages. Transformers are used widely in power transmission to increase voltages for efficient transfer and then step voltages down for safe distribution and usage. They experience losses from resistance in the coils and hysteresis and eddy currents in the core.
This document discusses transformer protection. It explains that protection is needed to minimize damage, prevent electric failure, reduce outages and costs. The document categorizes different types of transformer faults and classifications of protection functions. It describes differential protection, restricted earth fault protection, overflux protection and other monitoring systems like Buchholz relays, oil temperature indicators, pressure releases and air cell protectors. The document emphasizes the importance of protecting transformers from internal faults and abnormal operating conditions.
This document presents information about Buchholz relays. It discusses that Buchholz relays were first developed in 1921 and are installed in large power transformers to protect against internal faults. The relay contains an upper element that closes an alarm circuit during slow developing faults and a lower element that trips the circuit breaker during severe faults. It operates by detecting hydrogen gas generated from transformer oil decomposition during faults, with the gas causing floats that activate mercury switches to signal alarms or trip the transformer. Buchholz relays provide simple and effective protection for oil-immersed transformers while also detecting slow developing faults earlier than other methods.
The document discusses the Buchholz relay, which is a protective device used in oil-immersed transformers. It contains three elements: an upper float, lower element, and main element containing gas release pockets. It operates based on mechanical phenomena to detect minor faults through gas accumulation or major faults indicated by a surge of oil. The Buchholz relay alerts to faults and can isolate the transformer to prevent accidents, while also allowing analysis of fault gases. However, it only protects below the oil level and has some time delay.
Transformers are static devices, totally enclosed and generally oil immersed. Therefore, chances of faults occurring on them are very rare. But when fault occurring , It is very harmful for power system and our environment. So there are many protection system keep in back-up protection of power system safety.
This document describes various protection schemes for transformers, including differential, restricted earth fault, overcurrent, and thermal protection.
1) Differential protection compares currents entering and leaving the transformer zone to detect internal faults. It provides the best protection for internal faults.
2) Restricted earth fault protection is used to detect high-resistance winding-to-core faults not detectable by differential relays. It uses a neutral current transformer and is sensitive to internal earth faults.
3) Overcurrent protection uses relays with current coils to detect overloads and faults above a pickup threshold. It also includes ground-fault protection.
This document provides an overview of relays. It begins with an introduction to Minda Furukawa Electric Pvt. Ltd, a joint venture company that produces wiring harnesses and relay components. It then defines relays as switches that open and close circuits electromechanically or electronically to control one circuit by another. The document outlines the basic design of relays including their electromagnet, armature and contacts. It describes the main types of relays as electromechanical or solid state. Applications of relays include amplifying signals, isolating faults, and time delay functions. Advantages are their ability to control high voltage circuits with low signals and provide safety. A brief history of relays dates them back
This certificate from Nemko documents that circuit breakers manufactured by People Ele. Appliance Group Co., Ltd. for overcurrent protection ranging from 3 to 63A at 240/415V 50/60Hz were tested and found to comply with European standard EN 60898-1:2003. The certificate is valid provided any changes to the product are approved by Nemko and covers models RDB67-63 with 1, 2, 3, or 4 poles and an IP20 rating.
This certificate from Nemko documents that circuit breakers manufactured by People Ele. Appliance Group Co., Ltd. for overcurrent protection ranging from 3 to 63A at 240/415V 50/60Hz were tested and found to comply with European standard EN 60898-1:2003. The certificate is valid provided any changes to the product are approved by Nemko and covers models RDB67-63 with 1, 2, 3, or 4 poles and an IP20 rating.