diff --git a/PRMLibrary/PRMLibrary.cs b/PRMLibrary/PRMLibrary.cs
index d3d72db517d283ef8bb423546925a7e92221b43f..6c23ced81a8fd273b68b6f68cab8117882663024 100644
--- a/PRMLibrary/PRMLibrary.cs
+++ b/PRMLibrary/PRMLibrary.cs
@@ -23,6 +23,9 @@ namespace PRMLibrary
         /// <param name="Col">column index</param>
         public Index(int Row, int Col)
         {
+            if (Row <= -1 || Col <= -1) {
+                throw new Exception("Index must be initialized with nonegative integer value");
+            }
             this.Row = Row;
             this.Col = Col;
         }
@@ -201,22 +204,22 @@ namespace PRMLibrary
         /// <param name="ison"></param>
         /// <param name="toID"></param>
         /// <param name="fromID"></param>
-        public Powerline(List<Coordinate> coordinate, int id, int year, double height, int power, bool isbroken, bool ison, int toID, int fromID)
+        public Powerline(List<Coordinate> coordinates, int id, int year, double height, int power, int toID, int fromID)
         {
-            this.coords = coordinate;
+            this.coords = coordinates;
             this.identifier = id;
             this.year = year;
             this.height = height;
             this.power = power;
-            this.isbroken = isbroken;
-            this.ison = ison;
+            this.isbroken = false;
+            this.ison = false;
             this.pointFromID = fromID;
             this.pointToID = toID;
         }
         /// <summary>
         /// default constructor
         /// </summary>
-        public Powerline() : this(new List<Coordinate>(), -1, 0, 0, 0, false, false, -1, -1) { }
+        public Powerline() : this(new List<Coordinate>(), -1, 0, 0, 0, -1, -1) { }
     }
     /// <summary>
     /// powerstation/pole point class
@@ -266,7 +269,7 @@ namespace PRMLibrary
         /// <param name="sttype"></param>
         /// <param name="issource"></param>
         /// <param name="ison"></param>
-        public PowerStation(Coordinate crds, int id, string stname, int stpower, string sttype, bool issource, bool ison)
+        public PowerStation(Coordinate crds, int id, string stname, int stpower, string sttype, bool issource)
         {
             this.coords = crds;
             this.identifier = id;
@@ -274,12 +277,12 @@ namespace PRMLibrary
             this.power = stpower;
             this.type = sttype;
             this.issource = issource;
-            this.ison = ison;
+            this.ison = false;
         }
         /// <summary>
         /// default constructor
         /// </summary>
-        public PowerStation() : this(new Coordinate(), -1, "", 0, "", false, false) { }
+        public PowerStation() : this(new Coordinate(), -1, "", 0, "", false) { }
     }
 
     enum FunctionType
diff --git a/PRMLibrary/PRMLibrary.csproj b/PRMLibrary/PRMLibrary.csproj
index d8654bae031b10340997c18ed22549d69dbdfd80..caa9e9a123d1a887cf986af161057ada6e275123 100644
--- a/PRMLibrary/PRMLibrary.csproj
+++ b/PRMLibrary/PRMLibrary.csproj
@@ -32,10 +32,7 @@
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
-    <Reference Include="System.Core" />
-    <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="Microsoft.CSharp" />
-    <Reference Include="System.Data" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="PRMLibrary.cs" />