A stand-alone power system ( SAPS or SPS ), also known as remote area power supply ( RAPS ), is an off-the-grid electrical system for locations not equipped with an electrical distribution system. Typical SAPS includes one or more methods of power generation, energy storage, and regulation.
Electricity is usually produced by one or more of the following methods:
- The photovoltaic system uses solar panels
- Wind turbine
- Geothermal resources
- Combined heat and power
- Micro hydro
- Diesel generator or biofuel
- Thermoelectric Generator (TEG)
Storage is usually implemented as a battery bank, but other solutions exist including fuel cells. The power taken directly from the battery will be the extra low current direct voltage (DC ELV), and it is used primarily for lighting as well as for DC equipment. Inverters are used to generate low-voltage AC, which is where more typical devices can be used.
Standalone photovoltaic power systems are independent of utility networks and can use solar panels only or can be used in conjunction with diesel generators, wind turbines or batteries.
Video Stand-alone power system
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Two types of standalone photovoltaic power systems are direct-coupled systems without batteries and stand-alone systems with batteries.
Direct-coupled system
The basic model of a direct coupled system consists of solar panels that connect directly to the dc load. Since there is no battery bank in this setting, energy is not stored and hence it is capable of turning on common equipment such as fans, pumps, etc. Only during the day. MPPT is generally used to efficiently utilize solar energy especially for electrical loads such as positive-displacement water pumps. Impedance matching is also considered a design criterion in a direct-coupled system.
Stand-alone system with battery
In stand-alone photovoltaic power systems, the electrical energy generated by the photovoltaic panel can not always be used directly. Because demand from loads is not always the same as the capacity of solar panels, battery banks are generally used. The main functions of storage batteries in stand-alone PV systems are:
- Energy Storage Capacity and Autonomy : To store energy when there is excess available and to provide it when necessary.
- Current Voltage and Stabilization : To provide a stable current and voltage by eradicating transients.
- Supply Surge Flow : to provide a surge current to the load like a motor when needed.
Maps Stand-alone power system
Hybrid system
The hybrid power plant is a complete power supply system that can be easily configured to meet various remote power needs. There are three basic elements in the system - resources, batteries, and power management centers. Hybrid resources include wind turbines, diesel engine generators, thermoelectric generators and solar PV systems. The battery allows autonomous operation by compensating for the difference between production and power usage. The power management center regulates the power production of each source, controls power usage by classifying the load, and protecting the battery from service extremes.
System monitoring
Monitoring of photovoltaic systems can provide useful information about their operations and what to do to improve performance, but if data is not reported correctly, the effort is wasted. In order to be useful, the monitoring report should provide information on the relevant aspects of the operation in terms that are easily understood by third parties. Appropriate performance parameters must be selected, and their values ​​are updated consistently with each new issue of the report. In some cases, it may be useful to monitor the performance of individual components to improve and improve system performance, or be warned for loss of performance in time for precautions. For example, monitoring the charging/charging profile of the battery will signal when replacement is made before the end time of system failure is experienced.
Standard IEC 61724
IEC has provided a set of monitoring standards called "Standards for monitoring of Photovoltaic system performance" (IEC 61724). It focuses on the electrical performance of photovoltaic systems and it does not address hybrids or prescribe methods to ensure that a fair performance assessment.
Performance appraisal
Performance appraisals include:
- Data collection, which is an easy parameter measurement process. â € <â € <
- Evaluate the data in a way that provides useful information.
- Spreading useful information to end users.
Various kinds of load-related problems are identified to be classified into the following types:
- Incorrect selection : Some loads can not be used with stand-alone PV systems.
- Home cable : Inadequate or low quality cable and protection devices may affect system responses.
- Low efficiency : Low efficiency loads can increase energy consumption.
- Live launch : Standby mode of some wasted energy load.
- Start-up : High current drawn by multiple loads during start-up The current spike during start-up may temporarily overload the system.
- Reactive power : Circulating currents may differ from the currents consumed when capacitive or inductive loads are used.
- Harmonic distortion : Non-linear loads can create distortion of inverter waveform.
- Mismatch between load and inverter size : When higher rated inverters are used for lower capacity loads, overall efficiency is reduced.
Gallery
See also
References
External links
- RAPS
- Queensland RAPS paper
- The RAPS system schema
- Explain Africa, World Bank Group (WBG) initiative
Source of the article : Wikipedia
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