PV Basics series Summary: photovoltaic power plant main electric connection schemes are there?

Polaris solar PV net news: photovoltaic power plant main electric connection schemes are there?

Photovoltaic power plant main electric connection, mainly booster station main electrical connection, also known as electric wiring, refers to the transformers, circuit breakers, isolating switches, lightning arresters, transformers, capacitors, bus bar, a main electrical equipment such as power cables, according to a certain order of connecting circuits, usually represented by one-line diagram.

Primary electric design, to take into account the reliability, flexibility, ease of operation, economy and ease of expansion and other factors.

Typical main electrical wiring can be divided into two broad categories: according to the number of access points can be divided into a bus connection (that is, a single access point) and no bus connection (multiple access points). Including bus connection into a single (double) bus and single (double) bus segment in two ways, no bus connection modes can be divided into external bridge wiring way and the bridge connection.

, Bus connection mode

1. single Busbar system


Single bus bar connection has the advantage of simple, clear, less equipment, low investment, easy operation, conducive to expansion. Disadvantages of single Busbar system: reliability and flexibility, bus or bus isolator to disconnect all power supply before any maintenance or failures.

2. dual-bus switchgear

Busbar through Busbar contact breaker connection between the two groups, each lead wire and power branch is a bus bar disconnector circuit breaker and two respectively to the two bus bar.

Double bus wiring of advantages: overhaul any a article bus Shi not effects normal powered; overhaul bus isolation switch Shi only effects this branch powered (isolation switch cannot with load opened broken, needs points broken circuit breaker device rear can); work bus occurred fault Hou all branch can quickly recovery powered; special needs Shi can with bus contact circuit breaker device and system for earlier tied for and solutions column operation, so run scheduling flexible, and reliability high, also, equipment inputs cost high.

Second, no bus connection mode

1. the unit connection

Generating units exported directly through the transformer wiring into a high-pressure system, known as generation-transformer unit connection. On this basis, each of the main transformer high-voltage side directly connected to a transmission line, transmission alone, not required in switching stations of power plants, each q no electrical connection of the main transformer, called unit connection line of generator-transformer group.

Advantages of unit connection: simple wiring, switches, less equipment, small footprint, easy operation, the generator and main transformer low-voltage short circuit current measurement is reduced (because less feedback power point), and in particular its investment can be reduced to the minimum.

2. bridge wiring

So-called internal and external bridge wiring is based on bridge (shown in circuit breaker QF3) distance from transformers difference, called the bridge closer, distance is called a bridge, near to unit connection to the main circuit breaker (figure QF1 QF2) is used as a basis.

With inner bridge connection suitable for line maintenance more frequently, and does not require constant switching of transformer (transformer switching switching operation was rather tedious, you need to cut and QF3 QF1).

Wiring for outside suitable for shorter lines and transformers needs change frequently, and booster station has a tendency to power through.

Third, the cost comparison

These programmes, equipment investment costs from high order double Busbar way, single-bus way, bridge wiring wiring pattern, unit, single Busbar system (unit connection works for multiple access points, higher investment than single Busbar system).

Four, photovoltaic power plant main electric connection features

Photovoltaic power plant located in the end of grid, small installed capacity, investment and cut out for a system not influenced, so the PV plants may stop operating input power and cut out. At design time, and demands for the reliability of PV power is not a priority.

In principle, all the above programmes are suitable for PV power plant main electric connection, but considering the scale and number of access points, photovoltaic power stations should be relatively low priority investment programme. Therefore, the PV power plant main electric connection can use unit wiring bridge wiring or single Busbar system.

Original title: PV Basics series Summary: photovoltaic power plant main electric connection schemes are there?

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