Do you understand about RECLOSER ( PBO)??

COVER BEHIND THE AUTOMATIC (PBO) and RECLOSING RELAY
PBO (recloser) is the power breaker (PMT) equipped with control devices and reclosing relay Reclosing relay is relays that can detect the flow disturbances and ordered PMT open (trip) and shut down again.  

The fuction of reclosing relay / PBO PBO hook up to medium voltage air channels mounted on a frequent disorder phase short circuit to ground which is temporary in nature, serves to: • Normalize back medium voltage air channels or minimize disruption caused by temporary outages remain. • Security section in order to limit medium voltage air channels / localize the affected area.  

Type of Reclosing relay Based on the type of reclosing command to the PMT can be classified into two types of reclosing relays, namely: • Single-shot Reclosing Relay :Relay can only give orders to the PMT reclosing time and the new one can perform reclosing after blocking the last time, If there is interference with the blocking period of time, PMT trip and can not reclose again (lock - out).

 

picture 1: PBO relay with a time Reclose

• Multi Shot Reclosing Relay.
o This relay can give orders to the PMT reclosing more than once. Dead time between reclosing can be set the same or different .
o If an interruption occurs, the relay OCR / GFR trip gave orders to the PMT at the same time also mengarjakan (mengenergize) Reclosing relay. o After the dead time t 1 is very short (less than 0.6 seconds), reclose relay orders to the PMT.
o If the interference persists, the PMT will return trip and reclosing relays will perform the second reclose after the dead time t 2 which is quite long (between 15-60 seconds).
o If the interference persists, then the PMT would return trip and reclosing relays will perform the third reclose after the dead time t 3.
o If the interference is still present in the blocking period tB 3, the PMT will trip and lock out.
o The use of multi-shot reclosing should doisesuaikan with a duty cycle (duty cycle) of the PMT.

 

picture 2: Diagram of Multi-Shot Reclosing work time Relay

Characteristic Reclosing Relay

• Fast tripping : to anticipate a temporary interruption. 

• Delayed tripping : to coordinate with downstream safety. 

• When the disturbance was quickly lost in the PBO operation will reset back to its initial state. If an interruption occurs after the reset, PBO start counting from the beginning. 

• Repetitive: research recloser automatically after success. • Non-repetitive: it requires manual reset (in case of permanent impairment and if the disturbance had been released). • PBO or overcurrent relays Recloser is so characteristic of PBO and OCR is the same (see the characteristics of the OCR). 

How to work Pattern of Medium Voltage Network Configuration?

Pattern of Medium Voltage Network Configuration can be sorted into 4 major groups, namely:
1) Pure Radial Configuration
2) Open Loop Configuration (Open Ring) Non-spindle
3) spindle configuration
4) Configuration Spot Network.

In its operation, most systems operate Radial, very rarely a distribution system operates in a loop condition.

Existing systems in East Java Distribution PLN grounding system (high resistance) 500 ohms with a phase to ground fault current maximum of 23 Amperes.
Distribution equipment installed on the network is SSO (automatic section switch) Automatic voltage detection section is equipped with a Fault Indicator (FSI), OCR and DGR relay installed in cell 20 KV sub station / feeder.

There are 2 (two) types of SSO voltage detection is used, namely:
1. Tree Type divided into:
a. Tree Branch.
b. One Line Loop.
c. Two Line Loop.

The use of SSO Tree Type in the network configuration to:
a. Tree Branch used to Radial Interconnection system (automatic) and Loop System One feeder and the Open Loop System Two feeders.
b. One Line Loop is used only at the meeting on feeders Transline Loop System One feeder.
c. Two Line Loop is used only on the Open Loop System Two feeders and placed after the SSO Tree Branch.

Loop Type
Use of Loop Type SSO at the Open Loop System Two feeders, SSO this type mounted on the cusp of feeders with feeder transline transline one another in a single loop.

Setting time SSO Tree Type:
T 1 = time of closing (10 seconds).
T 2 = time to lock (5 seconds).
T 3 = time to open (0.5 seconds).

Setting time SSO Loop:

T 5> Tr + (n +1) T1

T 5 = start time did not feel the voltage regulator box from one side to the Loop SSO entry automatically, setting between 60 - 80 seconds.
T r = time to close behind Reclose-1 (60 sec)
n = number of SSO Tree Type in the feeders (the majority taken from one side of the feeder.

PBO (Reverse Automatic breakers) installed diesel 20 KV substations be set as follows:

- Reclose - 1 = 60 seconds
- Reclose - 2 = 180 seconds

Design Criteria for Medium Voltage Networks

Electric Power Distribution Systems for Medium Voltage to be developed is 20 KV Voltage Distribution System using air and or cable conductor medium voltage 20 KV with respect to the density of the load, the level of quality and reliability and customer needs.

Some of the criteria considered are:
1) Criteria for the density of the load
2) Pattern Configuration
3) Correlation Voltage Drop
4) Correlation of losses against the standard network.
5) Development of a New Network
6) Consistency between the network loading of standard loading pattern.

LOAD DENSITY CRITERIA
In designing an Electrical Network, please note the load density in units KVA / KM2, so it can be determined the type and length Conductor Conductor who will supply the load.
Density Criteria expenses include:
1) Lighter loads
Areas / Locations that have a lighter load when there are loads of less than 0.5 MVA per km2.

2) Medium Cost
Area / location that has the burden was when there were loads of between 0.5 to 1 MVA MVA per KM2.

3) Solid Expenses
Areas / Locations that have a solid load when there are loads above 1 MVA per KM2.

Power Distribution System

     Electric power distribution system is one part of a power system that starts from the incoming PMT substation up to the Tools Counters and Border (APP) at the consumer installation that serves to channel and distribute electricity from a central substation to the customer's load center customers directly or through substations, distribution substations (transformer substations) with an adequate quality of service standards and regulations. thus this distribution system into a separate system for the distribution unit has a component related equipment in its operations to distribute electricity. Where the system is a device elements arranged interdependence to achieve a certain goal by displaying the function assigned.

     Viewed from the voltage distribution system at this time can be divided into 2 types namely:

a. Primary distribution, often called the Medium Voltage Network System (JTM) with a nominal operating voltage of 20 kV / 11.6 kV.

b. Secondary distribution, often called the Low Voltage Network System (JTR) with a nominal operating voltage 380/220 volt.

     Previously operating voltage value that is used in the environment of PLN at medium voltage level varies is 6 KV, 12 KV and 20 KV as well as the low voltage level is 220/127 volts at a Five-Year Plan starting in 1970 we know the voltage changes PTR / PTM this intended to improve reliability and reduce network losses. 

Power Transmission

     Transmission function to channel the flow of electricity / power from central power plant to substation as a load center. Voltage substations receive on Holding (Vr) is the difference between the voltage vector send (Vs) with the voltage drop along the conductor of the transmission of multiplication current (I) with impedance (Z). Impedance is the vector sum of resistance (R) and reactance (X) Conductor Conductor where the longer the greater its R and X so that Z is also getting larger and consequently also the voltage drop greater IZ; thus small Vr. Permissible service voltage down to 10% of V nominal. Thus the network length is limited by the voltage drop.

                                           transmisi  Z =  R + J X         drop tegangan  = I Z

                                                                                           

                                                              Vr =  Vs  -  IZ
                

     For Vr meet the standards it should be the longer the transmission, the transmission voltage is raised. The output of the generator in the generator (big power) voltage until medium voltage in raising the voltage to high voltage (150 kV) / extra high (500 kV) using Step Up Transformer. Transmission Voltage Transformer is accepted by the substation (Transformers Step Down) and is derived from 150 kV to 20 kV, 500 kV to 150 kV and some of the 500 kV to 20 kV. Conductor ACSR transmission and Isolatornya made ​​of porcelain and the tower made ​​of iron construction. / steel and in certain cities using ground cables (150 kV).

What is the Electric Power Systems??

     Electric Power Systems said to be a collection / combination of components or electrical equipment such as generators, transformers, transmission lines, distribution channels and expenses that are interconnected and constitute a unity so as to form a system.

    
     In the world of electrical technical problems often arise issues where electricity is generally generated at certain places that are far from a collection of customers, while users of electricity or electric power customers are spread in all over the place. Thus, the delivery of electricity from a place called the center generates electricity get to where customers need a variety of technical handling. By using a block diagram of the electrical power system can be described as follows:

 

     Power was raised in centers such as Hydroelectric Power Plant, Power Plant, PLTG, Combined Cycle Power Plant, Power Plant and Diesel Power Plant and then distributed through a transmission line after the voltage is raised first by Raising the voltage transformer (step-up transformers) in the Central Electricity.