Parallel operation synchronization

Code of practice for maintenance of electrical switchgear for voltages above 36 kV Speeificiition for voltage regulation and parallel operation of a.c. synchronous generators Methods of testing plastics... 

This device controls the generator and maintains a steady-stale armature voltage automatically within the predefined limits. It also serves to control the reactive kVAr loading during a parallel operation or when the machine is being used as a synchronous condenser for reactive power compensation through a quadrature droop control (QDC) as noted below. 

This is a scheme introduced in the AVR circuit to adjust the reactive power (kVAr) of a machine during a parallel operation or when it is being used as a synchronous condenser. It prevents a reactive circulating current, l. ... 

Introduction DG set Operating parameters Theory of operation Guidelines on the selection of a DG set Types of loads Starting of a DG set Proteetion of a DG set Parallel operation Procedure of parallel operation Recommended protection for a synchronizing scheme Load sharing by two or more generators Total automation through PLCs... 

Method of testing. If the diesel is to be tested, it may be necessary for it to operate in parallel with the supply system in order to apply load. Synchronizing facilities will be needed and the fault levels during parallel operation must be assessed. 

Part 140 Specification for voltage regulation and parallel operation of AC synchronous generators. 

Induction generators cannot operate independently in an isolated system. They can only function in parallel with synchronous generators that regulate voltage and supply the kilovars necessary to overcome the lagging power of the induction generation. 

The notion of an atomic operation is important for synchronization. An atomic operation is one that is indivisible. Once initiated, it will continue to completion. There are usually a large number of synchronization primitives in a parallel computer, most commonly test and set primitives, or semaphores implemented in hardware (10). A test and set operation tests the current value of a variable and optionally sets a new value, all in one indivisible operation. 

First, the designer should choose the type of rectification technology that is most appropriate for the application. The choice is whether to use passive rectification in which semiconductor rectifiers are used or synchronous recification in which power MOSFE B are placed in parallel with a smaller passive rectifier. Synchronous rectifiers are typically used in battery operated portable products where the added efficiency, usually an added two to eight percent, is important to extend the operating life of the battery or in applications where heat is important. In today s switching power supplies, passive rectifiers can dissipate 40 to 60 percent of the total losses within the power supply. Synchronous rectifiers affect only the conduction loss, which can be reduced by as much as 90 percent. 

When an A.C. synchronous machine operating as a motor in parallel with other loads and an external supply system is over-excited the machine will contribute reactive kvar to the supply. The net effect of this will be to reduce the amount of reactive current drawn from the supply, and this will improve the overall system power factor. 

---