Articles
The Liverpool Cross
The Liverpool Cross refers to a reversal of the direction of rotation in the three-phase electricity system. In Liverpool, the three phase voltages rotate counter clockwise, in the order Red-Blue-Yellow. In the rest of Britain the phases are ordered Red-Yellow-Blue. This necessitates a cross of the Yellow and Blue phases wherever the National Grid meets the Liverpool distribution network. The cross is said to be unique in mainland UK.
G59/3 Voltage & Frequency Stability Tests Using DVS3 Mk 1 and Time Delay Relay
New stability test procedures, introduced in the G59/3 standard for Embedded Generator Connections, require precise timing. This is something that the DVS3 Mk 1, an industry standard set for G59 testing, cannot currently provide. This paper provides a reliable method for testing to the G59/3 standard using an external precision timer with the DVS3 Mk 1.
Proposed Future Power Generation
The most economic UK source of energy is identified following fuel efficiency considerations, asset creation costs and adequate analysis of grid losses and plant performance figures. This leads to a preferred configuration of distributed generation. The technical aspects of operating a distribution network with and without national grid connections are discussed. Contingency provisions for electricity production are explained. Disposal of low grade heat into the community is assessed as beneficial to particular industries and particularly for large scale soil warming in agriculture and CO2 utilisation in Horticulture.
Armour Currents in Single Core Cables - Generalised Method and Workbook
In 2004 a worksheet calculating armour currents in single core cables was created and placed on the PEC website. This worksheet referred to in this paper as the Original Worksheet, deals with up to 10 parallel cables arranged in a plane, but it was not fully tested.
Armour Currents in Single Core Cables.
Use of armoured single core cables in HV installations may be the designer's choice; easy to install and terminate and they contribute to good earthing, but there can be serious consequences if the flow of armour current is neglected.
Calculating current in a supplementary earth conductor.
When cable armour is insufficient to carry expected earth fault current for the necessary period of time, a supplementary earth cable can be provided.
Capacitive Currents in Unearthed HV Systems.
Although it is generally the practice to provide an earth path in HV systems, there are examples where this is not the case and the HV power system operates in isolation from earth. We call these unearthed systems. The term ungrounded is also used.
Control of Synchronous Generators with Droop and Cross-Current Compensation.
The excitation of a synchronous generator is usually done by an AVR (Automatic Voltage Regulator) that uses generator voltage and/or current as inputs in order to control its output to a pre-set value.
Nuisance Generator Differential Protection Trips in Real Time Situations.
The differential protection function of a generator relay uses the difference between current into and out of the generator in order to detect internal faults in the generator winding.