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Intelligent Power and Motor Control Centre (iPMCC)

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General rules of electrical installation design
Connection to the MV utility distribution network
Connection to the LV utility distribution network
MV and LV architecture selection guide
LV Distribution
Protection against electric shocks
Sizing and protection of conductors
LV switchgear: functions and selection
Overvoltage protection
Energy Efficiency in electrical distribution
Power Factor Correction
Power harmonics management
Characteristics of particular sources and loads
PhotoVoltaic (PV) installation
Residential and other special locations
ElectroMagnetic Compatibility (EMC)

Contents


iPMCC

iPMCC is a system integrating intelligent Motor Protection Relays (IMPR) in a highly dependable Power and Motor Control Centre switchboard. Connectivity to the supervision and control system is provided through an industrial communication network.
This solution is particularly used in large industrial sites and infrastructures, with continuous or hybrid process, and whenever continuity of service is a priority.

intelligent Motor Protection Relay

IMPR is the key component of an iPMCC. It is a microprocessor controlled device. Motor monitoring and protection is performed based on measurements from sensors, such as current transformers, voltage transformers (embedded or external), thermal sensor, earth leakage detector,… From these measurements and the settings, it determines fault conditions or potential risks for motors and operators.According to the motor protection model, an IMPR has the capability to detect many kinds of faults. It is a great improvement compared to thermal relay protection. Moreover, many complementary functions can be implemented by an IMPR: monitoring, alarming, fault recording, statistics, communications, etc…


Fig-N73.jpg

1: Tesys T motor protection relay with native communications capability. The protections are based on current and temperature.
2: Tesys T extension module integrating voltage measurement and protections.
4: Tesys T’s emdedded CT can measure the earth leakage current of 20%-500% of FLC (full load current). External CT can be used to get a better accuracy (0.02-10A).
5, 6, 7: Different kinds of Human Machine Interfaces (1-to-1, 1-to-8, and 1-to-Many).
Fig. N73: Example of motor control and protection architecture

Motor Control Centre

A Motor Control Centre (MCC) is an electrical switchboard which groups all motor starters of a process, in order to build a centralised installation. Motor starters management centralisation is requested in many industries and infrastructures, in order to facilitate operation and maintenance. Withdrawable MCC functional units (FU), a.k.a. drawers, are used in critical applications, as they are more convenient to manage in case of fault. The faulty motor starter can be replaced quickly, without shutting down the whole switchboard.

Fixed or disconnectable FUs can be used in less critical applications.

MCC-type ASSEMBLIES must be full-compliant to IEC 61439-1 and 61439-2 standards to guarantee availability, safety and reliability of the application. In an iPMCC configuration, design verification, especially temperature rise test, is essential because the IMPR (electronic device) is sensitive to heat. Furthermore, MCC should provide a dependable and reliable communication bus connection

An MCC is different from a universal cabinet in the way that a universal cabinet can only be used to accommodate a group of few motor starters. It has lower electrical characteristics requirements, and it does not provide the separation between motor starters in different functional units. Therefore, in an universal cabinet complete shutdown will be necessary before maintenance operations or any reconfiguration of the starters.

Fig-N73bis.jpg

Fig. N74: Example of iPMCC: Okken switchboard and drawers by Schneider Electric Compared to traditional solutions, an iPMCC offers great advantages in both the project design and execution stage as well as at the operations stage.

Value proposition for contractors during the project stage:

  • It improves project efficiency
    • Reduction of engineering work, as starters are more standardised over a wider range of ratings,
    • Reduction of on-site wiring time thanks to the use of field buses,
    • Reduction of set-up time thanks to remote parametrization of control motor devices.
  • It reduces commissioning time by
    • Allowing a better understanding of the process reactions thanks to detailed diagnostics and statistics,
    • Allowing faster error fixing and bug tracking,
    • Helping to fix process start-up problems,
    • Allowing time reduction thanks to pre-validated solutions (reference architectures).

Value proposition for end users during the operation stage:

  • Improved Continuity of Service
    • Increase process availability by better PROTECTING the motors & the loads,
      • Using more accurate sensors,
      • Using more accurate motor protection models.
  • Reduced untimely DOWNTIME
    • Alarms often give time to fix the problem before tripping occurs,
    • Trip conditions are detailed to help corrective operations,
    • Statistics can be used for continuous improvement,
    • Recording all protection parameters changes.
  • Reduced Operational Costs
    • Reduced ENERGY costs,
      • Reduced energy consumption,
      • Optimised energy consumption, benchmarking, costs allocation.
  • Reduced MAINTENANCE costs
    • Less downtime,
    • Faster problem fixing,
    • Less spare parts stock,
    • Preventive maintenance strategy.
  • Reduced EVOLUTION costs and time
    • Simplified engineering,
    • No wiring required,
    • Simplified set-up,
    • Easier process tuning and commissioning.

A complete iPMCC concentrates the knowledge and experience of electrical distribution, motor protection and control, automation and installation. This is why only a few leading companies in electrical distribution and automation can propose this kind of solution.