background preloader

Power Systems

Facebook Twitter

Next Generation Energy Storage: Beyond Lithium Ion. Aquion Energy Salt Water Batteries. Clean Disruption - Why Energy & Transportation will be Obsolete by 2030 - Oslo, March 2016. A Revolutionary New Battery for Grid Energy Storage with Donald Sadoway. Reinventing Batteries. How does Synchronization of alternators with the electrical grid achieved when there is a phase angle difference between the two systems? - Quora. Half the price in half the time: solar storage innovation harnesses new energy frontier. If Tesla’s Powerwall is the “Lamborghini” of the solar storage industry, a small Brisbane company backed by University of Queensland researchers says it has hit on the formula to deliver the “Toyota”.

Half the price in half the time: solar storage innovation harnesses new energy frontier

Redback Technologies, which last week inked a commercialisation deal with UQ, claims to have harnessed the power of algorithmic software and efficient design to produce the most cost-effective solar storage system on the Australian market. Despite relying on a smaller battery than the Powerwall – which is widely expected to be the catalyst for rapid growth of the solar storage market this year – Redback says its “Ouija board” system, available from June, will pay for itself in half the time. Redback’s founder and managing director, Philip Livingston, said it would take an average 5.6 years to earn back the Ouija’s $9,000 price tag through electricity bill savings, versus 11 years on the Powerwall’s $15,000 to $17,000 installation cost. Inbox - petert - BluePoint Mail. Earthing system. Regulations for earthing system vary considerably among countries and among different parts of electric systems.

Earthing system

Most low voltage systems connect one supply conductor to the earth (ground). Low-voltage systems[edit] In low-voltage distribution networks, which distribute the electric power to the widest class of end users, the main concern for design of earthing systems is safety of consumers who use the electric appliances and their protection against electric shocks. The earthing system, in combination with protective devices such as fuses and residual current devices, must ultimately ensure that a person must not come into touch with a metallic object whose potential relative to the person's potential exceeds a "safe" threshold, typically set at about 50 V. In most developed countries, 220/230/240 V sockets with earthed contacts were introduced either just before or soon after World War II, though with considerable national variation in popularity.

IEC terminology[edit] TN networks[edit] Hipot. Hipot is an abbreviation for high potential.


Traditionally, hipot is a term given to a class of electrical safety testing instruments used to verify electrical insulation in finished appliances, cables or other wired assemblies, printed circuit boards, electric motors, and transformers. Under normal conditions, any electrical device will produce a minimal amount of leakage current due to the voltages and internal capacitance present within the product. Yet due to design flaws or other factors, the insulation in a product can break down, resulting in excessive leakage current flow. This failure condition can cause shock or death to anyone that comes into contact with the faulty product. A hipot test (also called Dielectric Withstanding Voltage (DWV) test) verifies that the insulation of a product or component is sufficient to protect the operator from electrical shock.

Three types of hipot tests are commonly used. Dielectric Breakdown Test. Dielectric Withstanding Voltage Test. Circuit breaker. Switchgear. High voltage switchgear A section of a large switchgear panel, in this case, used to control on-board casino boat power generation.


Tram switchgear This circuit breaker uses both SF6 and air as insulation. The very earliest central power stations used simple open knife switches, mounted on insulating panels of marble or asbestos. Power levels and voltages rapidly escalated, making opening manually operated switches too dangerous for anything other than isolation of a de-energized circuit. The high-voltage switchgear was invented at the end of the 19th century for operating motors and other electric machines.[1] The technology has been improved over time and can now be used with voltages up to 1,100 kV.[2] Residual-current device. A two-pole residual-current device A residual-current device (RCD), or residual-current circuit breaker (RCCB) or residual twin-direct current couplet (R2D2), is an electrical wiring device that disconnects a circuit whenever it detects that the electric current is not balanced between the energized conductor and the return neutral conductor.

Such an imbalance may indicate current leakage through the body of a person who is grounded and accidentally touching the energized part of the circuit. A lethal shock can result from these conditions. RCCBs are designed to disconnect quickly enough to prevent injury caused by such shocks. Protective relay. In electrical engineering, a protective relay is a device designed to trip a circuit breaker when a fault is detected.

Protective relay

The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current, over-voltage, reverse power flow, over- and under- frequency. Microprocessor-based digital protection relays now emulate the original devices, as well as providing types of protection and supervision impractical with electromechanical relays. In many cases a single microprocessor relay provides functions that would take two or more electromechanical devices. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays. However, due to their very long life span, tens of thousands of these "silent sentinels" are still protecting transmission lines and electrical apparatus all over the world. Operation principles[edit] Introduction to protection & control (2012) Instrument transformer.

Instrument transformers are high accuracy class electrical devices used to isolate or transform voltage or current levels.

Instrument transformer

The most common usage of instrument transformers is to operate instruments or metering from high voltage or high current circuits, safely isolating secondary control circuitry from the high voltages or currents. The primary winding of the transformer is connected to the high voltage or high current circuit, and the meter or relay is connected to the secondary circuit. IRWIN 11.27: Three Phase Tutorial, currents in a delta. PHASOR 7b - (Version 2) Active, reactive, apparent and complex power.