Solar Circuit Breaker-An Essential Part In PV System
Table of Contents
The selection of a solar circuit breaker is an easy one to overlook in a solar PV system and time should be taken to choose the right solution. If the circuit breaker for solar is not appropriate, it can cause frequent tripping of equipment, overheating damage, and even system fires.
Therefore, in this post, we will focus on the circuit breaker solar from how it works to how to choose. You can also get the differences between solar circuit breakers and fuse. Keep scrolling.
What Is Solar Circuit Breaker?
A solar circuit breaker protects the user by tripping and cutting off the load power in the event of an error. Circuit breakers for solar systems are mainly used to switch various types of loads. Transformer isolation inverters require a bipolar DC solar circuit breaker or isolator rated at 1.25 times the solar PV array’s short-circuit current (Isc) rating and 1.2 times the open-circuit voltage (Voc).
Solar power circuit breakers are an important part of the solar PV system. Between direct current and alternating current, it acts as a barrier. The barrier between the panel and the AC power is necessary for installation and routine maintenance. Electrical protection requires the use of solar circuit breakers.
Since alternators can continue to operate even if they fail, solar circuit breakers are critical. When used, they may require less maintenance, are more reliable, and have a lower failure rate. To better understand why solar circuit breakers are so important for solar systems, this blog will attempt to do just that. Circuit breakers for solar power systems are necessary to guarantee the quality and durability of photovoltaic panels.
How Does Solar Power Circuit Breaker Work?
Thermal Protection Mechanism
A basic question is, how does a DC solar circuit breaker actually work? DC solar circuit breakers use both thermal and magnetic protection methods.
With thermal protection, the solar circuit breaker trips if the current rating is exceeded. When more heat is generated, the bimetallic contacts heat up and expand. The thermal protection helps when the current is overloaded.
Magnetic Protection in DC Solar Circuit Breakers
In the presence of magnetic protection in the DC solar circuit breaker, it will trip the DC solar circuit breaker when the fault current is present in large quantities. DC solar circuit breakers have the ability to interrupt fault currents even at their highest stage. Magnetic protections in DC solar circuit breakers are important because they prevent short circuits and other faults.
Importance in Solar Panel and Electric Vehicle Systems
Especially in response to systems with installed solar photovoltaic panels, circuit breaker solar are critical. The solar panel circuit is the expensive part of the system. Therefore, it is very important to protect it by means of circuit breaker for solar. All circuits of the solar photovoltaic panel are connected to the combiner box. Additionally, solar power circuit breaker protect circuits and panels.
Solar radiation received by photovoltaic solar panels can be converted into direct current. DC solar circuit breakers are essential for PV installations. Even a small mismatch can cost a fortune. In the case of electric vehicles, their batteries are charged with the help of electric vehicle charging stations. The system here is consistent with direct current. Therefore, DC solar circuit breakers must be installed in these systems to avoid any accidents.
Photovoltaic solar panels and electric vehicles work well together because they primarily deal with direct current. Furthermore, this conversion of direct current to alternating current is not mandatory. DC solar circuit breakers make it easy to control automation systems. This is done so that they can provide a quick response.
How to Apply Solar Circuit Breaker?
Solar panel owners can use direct current in their homes for a variety of purposes. In these cases, a DC solar circuit breaker is required for shielding. Many different solutions need to be developed. In addition, they need to set up a separate fuse box that contains many solar power circuit breaker for AC and DC power. Circuit breaker for solar have the ability to control the direction of the current.
Therefore, accidental or intentional changes in direction can raise safety issues and damage solar cells. In the case of LED lights, they can be powered using light-emitting diodes. However, this function can only be performed in the presence of a direct current.
Solar Circuit Breaker VS Fuse
The main difference between a solar circuit breaker and a fuse is that a solar circuit breaker mechanically cuts off the connection once the electrical load exceeds the power source. In this way, fires and other problems with the connected equipment are prevented. On the other hand, if the input current is greater than the required current, the fuse prevents damage to the particular device.
Reusability
If the input current is greater than the current required by the device, the fuse will blow but can no longer be used after that. solar circuit breakers, on the other hand, operate by mechanically tripping and cutting connections. It can be easily reopened, allowing multiple uses.
Operation Principles
Fuses use conductive materials, and when the current exceeds the required level, their electrical and thermal properties are compromised, while solar circuit breakers interrupt the connection electromagnetically.
Response Time
The fuse response time is 0.002 seconds, while the solar circuit breaker response time is between 0.02 and 0.05 seconds. Due to the speed at which metal fuses melt, fuses have an advantage over circuit breaker solar because they interrupt the flow of power faster. However, due to this melting process, the fuse eventually needs to be replaced. When the circuit is disconnected, simply reset the solar circuit breaker for solar.
Cost
Installation and maintenance costs are the main factors to consider when choosing an electrical system for a home. Installing a solar power circuit breaker in your home can be expensive. This is because the components of the solar circuit breaker are expensive and the system is complex. The time it takes for a solar circuit breaker to react to a home spike in electricity usage is another important factor. During surges, your electrical equipment can be damaged because solar circuit breakers do not react to surges for a few minutes. In addition, fuses can provide a higher level of protection, as they can stop the flow of energy almost instantaneously. However, a circuit breaker for solar can still offer good protection, and a solar power circuit breaker is designed to handle the specific needs of solar-powered systems.
Application
The various uses of solar circuit breakers and fuses are another important factor to consider. For example, fuses are typically used in homes with moderate electrical loads and electronic devices with low current consumption. Solar circuit breakers, however, are used for motors and other heavy machinery that consume a lot of electricity. This is an important factor to consider for buildings where the increased electrical load may outweigh a traditional fuse system. A solar circuit breaker protects the entire home, not just one or two pieces of electronic equipment. The fuses only cover certain gadgets, not the entire house or apartment. And this is crucial when selecting a fuse box and solar circuit breaker for solar or solar power circuit breaker.
The solar circuit breaker will show its operating status and if it needs to be serviced. On the other hand, fuses do not show their operating status.
Protection
Solar circuit breakers protect homes and equipment from overloads and short circuits, while fuses can only handle overloads. This is an important difference to keep it in mind when choosing one.
How to Calculate Solar Circuit Breakers in Solar PV System?
The maximum continuous output current of the inverter is multiplied by this factor.
For example, 30A x 1.25 = 37.5A
Round the rated size determined in step 1 to the nearest common size of the solar circuit breaker.
So the formula is simply the inverter’s maximum output current multiplied by a 125% safety factor, rounded to the nearest breaker size.
How to Choose a Suitable Solar Circuit Breaker?
Ambient temperature around the cable
In the case of photovoltaic systems, cables are usually laid outdoors (open-air systems, flat roof systems, etc.). It is generally assumed that the outdoor ambient temperature will be higher than the installation temperature in the building. Due to the increase in ambient temperature, the ampacity load decreases.
Mutual heating of solar circuit breakers
In photovoltaic systems, inverters that simultaneously input maximum current (simultaneity) are also usually connected to adjacent circuit breaker solar. This causes the circuit breaker solar to heat up faster, which can lead to premature tripping. To ensure adequate heat dissipation and prevent premature tripping, large gaps must be maintained between the individual circuit breaker solar.
To calculate the heat loss, the correction factor is specified in the technical data of the circuit breaker solar. For example, for a row of nine devices, this correction factor can be specified as 0.77. A circuit breaker solar with a nominal current of 50 A will behave as if its nominal current is 0.77 x 50 A = 38.5 A.
If this current is insufficient, a circuit breaker solar with a higher nominal current can be used. Always remember that depending on the situation (without simultaneity), the fuse does not trip until it reaches its nominal current. In this case, the connection cable must have an appropriate current carrying capacity or need to be replaced with a cable with a larger cross-section.
Another possibility is to increase the distance between circuit breaker for solar. This dissipates more heat, which prevents accidental tripping.
Ambient temperature at the solar circuit breaker
Due to the simultaneity described earlier, the amount of heating of the distribution board where the solar power circuit breaker is installed may exceed the normal value of a conventional installation. Since the distribution board in the photovoltaic system is usually installed in the open air, the temperature in the distribution board is higher. Data on the screening factors for this effect are specified in the technical data of the circuit breaker solar.
Type of connected device
Refer to the installation manual for the appropriate characteristics of the respective inverter. The load disconnect feature of the circuit breaker for solar can be used to disconnect the inverter from the utility grid under load. Screw-type fuse elements such as DIAZED fuses or NEOZED fuses do not have load disconnect characteristics and can therefore be used as cable protection, but must not be used as disconnectors. When disconnected under load, the fuse element may be destroyed or its function impaired due to contact erosion. No additional load is required between the circuit breaker for solar and the inverter.
The Number of Strings in the Isolator
If there are two poles, only one string should exist. When there are two poles, there should be two strings. You can choose from multiple string panels of isolators for transmitting external direct currents. A single maximum power point tracker can also be used as a converter, compatible with universal string inverters with built-in DC isolators.
Size of the System’s Voltage
The isolator carrying the operating voltage should have a voltage higher than or equal to the voltage required by the system. The most typical specifications are 1500V, UL508i 600V, and IEC60947-3 1000V, although single-phase inverters connected to the system voltage can usually operate at 600V. The system voltage of the three-phase string inverter can be up to 1000V and 1500V. The same is true for centralized inverters.
Conclusion
The DC solar circuit breakers are an important part of a photovoltaic system. Without their protection, PV panels may be more easily damaged and system failures may occur. Both AC solar circuit breakers and DC circuit breaker solar play their respective roles in the system. This is why they are both very important for proper operation. If proper wiring techniques, safety measures, maintenance, and procedures are followed, DC circuit breaker for solar can serve as the prominent protection needed for many systems such as photovoltaic panels.
Depending on their capacity, solar PV panels may have one or more devices. DC solar power circuit breakers are required to protect the circuit connected to the photovoltaic combiner box. Solar panels can be used with unidirectional current outputs, thanks to the way all the power passes through them.
If there are many DC load panels, many circuit breaker solar need to be installed. Solar panel owners are able to use direct current in their homes for a variety of purposes. In these cases, a circuit breaker for solar is necessary for shielding. Many different solutions need to be developed. Therefore, I hope that after reading this article, you can learn a little more about solar power circuit breaker.